feat(search): 'why this matched' highlights (ts_headline)

Slice 3 of search-core. Search results now show WHY they matched: a ts_headline
body fragment with matched terms highlighted. The API returns U+E000/U+E001
sentinels around matches (NOT HTML); the client tokenises them into escaped
<mark> React elements, so untrusted email content can never inject markup (no
dangerouslySetInnerHTML). Subtle accent tint. Only when there's a free-text query
(browse unchanged); projection branched (no DB function in a ternary) for
unambiguous EF translation.

Verified: build + all 40 tests; ts_headline output shape in raw Postgres; and the
ranked+headline EF query proven to translate + execute against a live Postgres via
a throwaway test (removed).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/components/EmailRow.jsx

@@ -16,6 +16,25 @@ const fmtSize = (b) => {
   return `${(b / 1048576).toFixed(1)} MB`;
 };
 
+// "Why this matched": the API wraps matched terms in U+E000/U+E001 sentinels (NOT HTML).
+// We tokenise and render the highlighted parts as <mark> React elements — React escapes
+// all text nodes, so untrusted email content can never inject markup (no dangerouslySetInnerHTML).
+const HL_START = String.fromCharCode(0xE000);
+const HL_STOP = String.fromCharCode(0xE001);
+const HL_RE = new RegExp(HL_START + '([\s\S]*?)' + HL_STOP, 'g');
+function renderHighlight(s) {
+  const out = [];
+  let last = 0, key = 0, m;
+  HL_RE.lastIndex = 0;
+  while ((m = HL_RE.exec(s)) !== null) {
+    if (m.index > last) out.push(s.slice(last, m.index));
+    out.push(<mark key={key++}>{m[1]}</mark>);
+    last = HL_RE.lastIndex;
+  }
+  if (last < s.length) out.push(s.slice(last));
+  return out;
+}
+
 export default function EmailRow({ email: initial, onRemove, selected, onToggleSelect, focused }) {
   const [email, setEmail] = useState(initial);
   const [acting, setActing] = useState(false);
@@ -83,7 +102,9 @@ export default function EmailRow({ email: initial, onRemove, selected, onToggleS
       </td>
       <td className="el-subject">
         <span className="el-subj-text">{email.subject || '(no subject)'}</span>
-        {email.snippet && <span className="el-snippet"> — {email.snippet}</span>}
+        {email.matchHighlight
+          ? <span className="el-snippet"> — {renderHighlight(email.matchHighlight)}</span>
+          : email.snippet && <span className="el-snippet"> — {email.snippet}</span>}
       </td>
       <td className="el-meta">
         {email.hasAttachments && <span className="el-attach" title="Has attachment">📎</span>}

frontend/src/index.css

@@ -64,6 +64,14 @@
     border-color: hsl(var(--border));
   }
 
+  /* Search "why this matched" highlight — subtle accent tint, not the default yellow. */
+  mark {
+    background: hsl(var(--primary) / 0.22);
+    color: inherit;
+    border-radius: 3px;
+    padding: 0 1px;
+  }
+
   body {
     @apply bg-background text-foreground antialiased;
     /* Inter (variable, self-hosted via @fontsource-variable/inter); system fallback. */

src/InboxIntel.Application/DTOs/EmailDtos.cs

@@ -16,7 +16,12 @@ public record EmailSummaryDto(
     long SizeEstimateBytes,
     EmailCategory Category,
     bool HasListUnsubscribe,
-    bool SupportsOneClick);
+    bool SupportsOneClick,
+    // "Why this matched": a ts_headline fragment of the body with matched terms wrapped in
+    // U+E000/U+E001 sentinels (NOT HTML — the client renders them as escaped <mark> elements,
+    // so untrusted email content can never inject markup). Null unless the search had a
+    // free-text query. Optional/last so other DTO constructors are unaffected.
+    string? MatchHighlight = null);
 
 /// <summary>Full single-email view, including body text, for the detail pane.</summary>
 public record EmailDetailDto(

src/InboxIntel.Infrastructure/Migrations/20260701192100_WeightSearchVectorSubjectBody.Designer.cs

@@ -0,0 +1,742 @@
+// <auto-generated />
+using System;
+using InboxIntel.Infrastructure.Persistence;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
+using NpgsqlTypes;
+
+#nullable disable
+
+namespace InboxIntel.Infrastructure.Migrations
+{
+    [DbContext(typeof(AppDbContext))]
+    [Migration("20260701192100_WeightSearchVectorSubjectBody")]
+    partial class WeightSearchVectorSubjectBody
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "8.0.4")
+                .HasAnnotation("Relational:MaxIdentifierLength", 63);
+
+            NpgsqlModelBuilderExtensions.UseIdentityByDefaultColumns(modelBuilder);
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.AnalyticsAggregate", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset>("CreatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<DateOnly>("Day")
+                        .HasColumnType("date");
+
+                    b.Property<string>("HourHistogramJson")
+                        .HasColumnType("text");
+
+                    b.Property<int>("NewsletterCount")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("TotalReceived")
+                        .HasColumnType("integer");
+
+                    b.Property<long>("TotalSizeBytes")
+                        .HasColumnType("bigint");
+
+                    b.Property<int>("TotalUnread")
+                        .HasColumnType("integer");
+
+                    b.Property<DateTimeOffset?>("UpdatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("uuid");
+
+                    b.Property<int>("WithAttachments")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("UserId", "Day")
+                        .IsUnique();
+
+                    b.ToTable("analytics_aggregates", (string)null);
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.Attachment", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset>("CreatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<Guid>("EmailId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("FileName")
+                        .IsRequired()
+                        .HasMaxLength(512)
+                        .HasColumnType("character varying(512)");
+
+                    b.Property<string>("GmailAttachmentId")
+                        .HasColumnType("text");
+
+                    b.Property<string>("MimeType")
+                        .HasMaxLength(255)
+                        .HasColumnType("character varying(255)");
+
+                    b.Property<long>("SizeBytes")
+                        .HasColumnType("bigint");
+
+                    b.Property<DateTimeOffset?>("UpdatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("uuid");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("EmailId");
+
+                    b.HasIndex("UserId", "MimeType");
+
+                    b.ToTable("attachments", (string)null);
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.Email", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("BodyText")
+                        .HasColumnType("text");
+
+                    b.Property<int>("Category")
+                        .HasColumnType("integer");
+
+                    b.Property<DateTimeOffset>("CreatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("GmailMessageId")
+                        .IsRequired()
+                        .HasMaxLength(64)
+                        .HasColumnType("character varying(64)");
+
+                    b.Property<bool>("HasAttachments")
+                        .HasColumnType("boolean");
+
+                    b.Property<bool>("HasListUnsubscribe")
+                        .HasColumnType("boolean");
+
+                    b.Property<bool>("IsImportant")
+                        .HasColumnType("boolean");
+
+                    b.Property<bool>("IsInInbox")
+                        .HasColumnType("boolean");
+
+                    b.Property<bool>("IsStarred")
+                        .HasColumnType("boolean");
+
+                    b.Property<bool>("IsTrashed")
+                        .HasColumnType("boolean");
+
+                    b.Property<bool>("IsUnread")
+                        .HasColumnType("boolean");
+
+                    b.Property<string>("ListUnsubscribeRaw")
+                        .HasMaxLength(2048)
+                        .HasColumnType("character varying(2048)");
+
+                    b.Property<DateTimeOffset?>("ReceivedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<NpgsqlTsVector>("SearchVector")
+                        .ValueGeneratedOnAddOrUpdate()
+                        .HasColumnType("tsvector")
+                        .HasComputedColumnSql("setweight(to_tsvector('english', coalesce(\"Subject\",'')), 'A') || setweight(to_tsvector('english', coalesce(\"BodyText\",'')), 'B')", true);
+
+                    b.Property<Guid>("SenderId")
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset>("SentAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<long>("SizeEstimateBytes")
+                        .HasColumnType("bigint");
+
+                    b.Property<string>("Snippet")
+                        .HasMaxLength(2048)
+                        .HasColumnType("character varying(2048)");
+
+                    b.Property<string>("Subject")
+                        .HasMaxLength(1024)
+                        .HasColumnType("character varying(1024)");
+
+                    b.Property<bool>("SupportsOneClickUnsubscribe")
+                        .HasColumnType("boolean");
+
+                    b.Property<Guid>("ThreadId")
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset?>("UpdatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("uuid");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SearchVector");
+
+                    NpgsqlIndexBuilderExtensions.HasMethod(b.HasIndex("SearchVector"), "GIN");
+
+                    b.HasIndex("SenderId");
+
+                    b.HasIndex("ThreadId");
+
+                    b.HasIndex("UserId", "Category");
+
+                    b.HasIndex("UserId", "GmailMessageId")
+                        .IsUnique();
+
+                    b.HasIndex("UserId", "IsInInbox");
+
+                    b.HasIndex("UserId", "IsUnread");
+
+                    b.HasIndex("UserId", "SenderId");
+
+                    b.HasIndex("UserId", "SentAtUtc");
+
+                    b.ToTable("emails", (string)null);
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.EmailLabel", b =>
+                {
+                    b.Property<Guid>("EmailId")
+                        .HasColumnType("uuid");
+
+                    b.Property<Guid>("LabelId")
+                        .HasColumnType("uuid");
+
+                    b.HasKey("EmailId", "LabelId");
+
+                    b.HasIndex("LabelId");
+
+                    b.ToTable("email_labels", (string)null);
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.Label", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("ColorHex")
+                        .HasColumnType("text");
+
+                    b.Property<DateTimeOffset>("CreatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("GmailLabelId")
+                        .IsRequired()
+                        .HasMaxLength(64)
+                        .HasColumnType("character varying(64)");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasMaxLength(255)
+                        .HasColumnType("character varying(255)");
+
+                    b.Property<string>("Type")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.Property<DateTimeOffset?>("UpdatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("uuid");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("UserId", "GmailLabelId")
+                        .IsUnique();
+
+                    b.ToTable("labels", (string)null);
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.MailDomain", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset>("CreatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<int>("EmailCount")
+                        .HasColumnType("integer");
+
+                    b.Property<bool>("IsBulkSender")
+                        .HasColumnType("boolean");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasMaxLength(255)
+                        .HasColumnType("character varying(255)");
+
+                    b.Property<DateTimeOffset?>("UpdatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("uuid");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("UserId", "Name")
+                        .IsUnique();
+
+                    b.ToTable("domains", (string)null);
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.MailThread", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset>("CreatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<DateTimeOffset?>("FirstMessageUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("GmailThreadId")
+                        .IsRequired()
+                        .HasMaxLength(64)
+                        .HasColumnType("character varying(64)");
+
+                    b.Property<DateTimeOffset?>("LastMessageUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<int>("MessageCount")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("Snippet")
+                        .HasColumnType("text");
+
+                    b.Property<string>("Subject")
+                        .HasMaxLength(1024)
+                        .HasColumnType("character varying(1024)");
+
+                    b.Property<DateTimeOffset?>("UpdatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("uuid");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("UserId", "GmailThreadId")
+                        .IsUnique();
+
+                    b.ToTable("threads", (string)null);
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.Sender", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("Address")
+                        .IsRequired()
+                        .HasMaxLength(320)
+                        .HasColumnType("character varying(320)");
+
+                    b.Property<DateTimeOffset>("CreatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("DisplayName")
+                        .HasMaxLength(255)
+                        .HasColumnType("character varying(255)");
+
+                    b.Property<Guid>("DomainId")
+                        .HasColumnType("uuid");
+
+                    b.Property<int>("EmailCount")
+                        .HasColumnType("integer");
+
+                    b.Property<bool>("HasUnsubscribe")
+                        .HasColumnType("boolean");
+
+                    b.Property<DateTimeOffset?>("LastReceivedUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<long>("TotalSizeBytes")
+                        .HasColumnType("bigint");
+
+                    b.Property<int>("UnreadCount")
+                        .HasColumnType("integer");
+
+                    b.Property<DateTimeOffset?>("UpdatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("uuid");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("DomainId");
+
+                    b.HasIndex("UserId", "Address")
+                        .IsUnique();
+
+                    b.HasIndex("UserId", "EmailCount");
+
+                    b.ToTable("senders", (string)null);
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.SyncState", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset?>("CompletedUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<int>("ConsecutiveFailures")
+                        .HasColumnType("integer");
+
+                    b.Property<DateTimeOffset>("CreatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("LastError")
+                        .HasMaxLength(4000)
+                        .HasColumnType("character varying(4000)");
+
+                    b.Property<string>("LastHistoryId")
+                        .HasColumnType("text");
+
+                    b.Property<DateTimeOffset?>("LastSuccessfulSyncUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<int>("LastSyncType")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("MessagesProcessed")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("ResumePageToken")
+                        .HasColumnType("text");
+
+                    b.Property<DateTimeOffset?>("StartedUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<int>("Status")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("TotalMessagesEstimate")
+                        .HasColumnType("integer");
+
+                    b.Property<DateTimeOffset?>("UpdatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("uuid");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("UserId")
+                        .IsUnique();
+
+                    b.ToTable("sync_states", (string)null);
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.UnsubscribeItem", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<double>("Confidence")
+                        .HasColumnType("double precision");
+
+                    b.Property<DateTimeOffset>("CreatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<int>("EmailCount")
+                        .HasColumnType("integer");
+
+                    b.Property<DateTimeOffset?>("LastAttemptUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<int>("Method")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("ResultMessage")
+                        .HasColumnType("text");
+
+                    b.Property<Guid>("SenderId")
+                        .HasColumnType("uuid");
+
+                    b.Property<int>("Status")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("UnsubscribeTarget")
+                        .HasMaxLength(2048)
+                        .HasColumnType("character varying(2048)");
+
+                    b.Property<DateTimeOffset?>("UpdatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("uuid");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("SenderId");
+
+                    b.HasIndex("UserId", "SenderId")
+                        .IsUnique();
+
+                    b.ToTable("unsubscribe_items", (string)null);
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.User", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset?>("AccessTokenExpiresAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<DateTimeOffset>("CreatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<bool>("DigestEnabled")
+                        .HasColumnType("boolean");
+
+                    b.Property<string>("DisplayName")
+                        .HasColumnType("text");
+
+                    b.Property<string>("Email")
+                        .IsRequired()
+                        .HasMaxLength(320)
+                        .HasColumnType("character varying(320)");
+
+                    b.Property<byte[]>("EncryptedRefreshToken")
+                        .HasColumnType("bytea");
+
+                    b.Property<string>("GoogleSubjectId")
+                        .IsRequired()
+                        .HasMaxLength(64)
+                        .HasColumnType("character varying(64)");
+
+                    b.Property<DateTimeOffset?>("LastDigestSentUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<DateTimeOffset?>("LastLoginUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("PictureUrl")
+                        .HasColumnType("text");
+
+                    b.Property<DateTimeOffset?>("UpdatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Email")
+                        .IsUnique();
+
+                    b.HasIndex("GoogleSubjectId")
+                        .IsUnique();
+
+                    b.ToTable("users", (string)null);
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.WidgetLayout", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset>("CreatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<int>("H")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("SettingsJson")
+                        .HasColumnType("text");
+
+                    b.Property<int>("SortOrder")
+                        .HasColumnType("integer");
+
+                    b.Property<DateTimeOffset?>("UpdatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("uuid");
+
+                    b.Property<bool>("Visible")
+                        .HasColumnType("boolean");
+
+                    b.Property<int>("W")
+                        .HasColumnType("integer");
+
+                    b.Property<string>("WidgetKey")
+                        .IsRequired()
+                        .HasMaxLength(64)
+                        .HasColumnType("character varying(64)");
+
+                    b.Property<int>("X")
+                        .HasColumnType("integer");
+
+                    b.Property<int>("Y")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("UserId", "WidgetKey")
+                        .IsUnique();
+
+                    b.ToTable("widget_layouts", (string)null);
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.Attachment", b =>
+                {
+                    b.HasOne("InboxIntel.Domain.Entities.Email", "Email")
+                        .WithMany("Attachments")
+                        .HasForeignKey("EmailId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Email");
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.Email", b =>
+                {
+                    b.HasOne("InboxIntel.Domain.Entities.Sender", "Sender")
+                        .WithMany("Emails")
+                        .HasForeignKey("SenderId")
+                        .OnDelete(DeleteBehavior.Restrict)
+                        .IsRequired();
+
+                    b.HasOne("InboxIntel.Domain.Entities.MailThread", "Thread")
+                        .WithMany("Emails")
+                        .HasForeignKey("ThreadId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("InboxIntel.Domain.Entities.User", null)
+                        .WithMany("Emails")
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Sender");
+
+                    b.Navigation("Thread");
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.EmailLabel", b =>
+                {
+                    b.HasOne("InboxIntel.Domain.Entities.Email", "Email")
+                        .WithMany("EmailLabels")
+                        .HasForeignKey("EmailId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("InboxIntel.Domain.Entities.Label", "Label")
+                        .WithMany("EmailLabels")
+                        .HasForeignKey("LabelId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Email");
+
+                    b.Navigation("Label");
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.Sender", b =>
+                {
+                    b.HasOne("InboxIntel.Domain.Entities.MailDomain", "Domain")
+                        .WithMany("Senders")
+                        .HasForeignKey("DomainId")
+                        .OnDelete(DeleteBehavior.Restrict)
+                        .IsRequired();
+
+                    b.Navigation("Domain");
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.UnsubscribeItem", b =>
+                {
+                    b.HasOne("InboxIntel.Domain.Entities.Sender", "Sender")
+                        .WithMany()
+                        .HasForeignKey("SenderId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Sender");
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.WidgetLayout", b =>
+                {
+                    b.HasOne("InboxIntel.Domain.Entities.User", null)
+                        .WithMany("WidgetLayouts")
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.Email", b =>
+                {
+                    b.Navigation("Attachments");
+
+                    b.Navigation("EmailLabels");
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.Label", b =>
+                {
+                    b.Navigation("EmailLabels");
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.MailDomain", b =>
+                {
+                    b.Navigation("Senders");
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.MailThread", b =>
+                {
+                    b.Navigation("Emails");
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.Sender", b =>
+                {
+                    b.Navigation("Emails");
+                });
+
+            modelBuilder.Entity("InboxIntel.Domain.Entities.User", b =>
+                {
+                    b.Navigation("Emails");
+
+                    b.Navigation("WidgetLayouts");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

src/InboxIntel.Infrastructure/Migrations/20260701192100_WeightSearchVectorSubjectBody.cs

@@ -0,0 +1,45 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+using NpgsqlTypes;
+
+#nullable disable
+
+namespace InboxIntel.Infrastructure.Migrations
+{
+    /// <inheritdoc />
+    public partial class WeightSearchVectorSubjectBody : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AlterColumn<NpgsqlTsVector>(
+                name: "SearchVector",
+                table: "emails",
+                type: "tsvector",
+                nullable: true,
+                computedColumnSql: "setweight(to_tsvector('english', coalesce(\"Subject\",'')), 'A') || setweight(to_tsvector('english', coalesce(\"BodyText\",'')), 'B')",
+                stored: true,
+                oldClrType: typeof(NpgsqlTsVector),
+                oldType: "tsvector",
+                oldNullable: true,
+                oldComputedColumnSql: "to_tsvector('english', coalesce(\"Subject\",'') || ' ' || coalesce(\"BodyText\",''))",
+                oldStored: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AlterColumn<NpgsqlTsVector>(
+                name: "SearchVector",
+                table: "emails",
+                type: "tsvector",
+                nullable: true,
+                computedColumnSql: "to_tsvector('english', coalesce(\"Subject\",'') || ' ' || coalesce(\"BodyText\",''))",
+                stored: true,
+                oldClrType: typeof(NpgsqlTsVector),
+                oldType: "tsvector",
+                oldNullable: true,
+                oldComputedColumnSql: "setweight(to_tsvector('english', coalesce(\"Subject\",'')), 'A') || setweight(to_tsvector('english', coalesce(\"BodyText\",'')), 'B')",
+                oldStored: true);
+        }
+    }
+}

src/InboxIntel.Infrastructure/Migrations/AppDbContextModelSnapshot.cs

@@ -160,7 +160,7 @@ namespace InboxIntel.Infrastructure.Migrations
                     b.Property<NpgsqlTsVector>("SearchVector")
                         .ValueGeneratedOnAddOrUpdate()
                         .HasColumnType("tsvector")
-                        .HasComputedColumnSql("to_tsvector('english', coalesce(\"Subject\",'') || ' ' || coalesce(\"BodyText\",''))", true);
+                        .HasComputedColumnSql("setweight(to_tsvector('english', coalesce(\"Subject\",'')), 'A') || setweight(to_tsvector('english', coalesce(\"BodyText\",'')), 'B')", true);
 
                     b.Property<Guid>("SenderId")
                         .HasColumnType("uuid");

src/InboxIntel.Infrastructure/Persistence/AppDbContext.cs

@@ -59,15 +59,17 @@ public class AppDbContext : DbContext, IAppDbContext
         modelBuilder.Entity<UnsubscribeItem>().HasQueryFilter(e => CurrentUserId == Guid.Empty || e.UserId == CurrentUserId);
 
         // PostgreSQL full-text search: generated tsvector over subject + body with a
-        // GIN index, maintained by the DB and read-only in code. The tsvector type is
-        // Npgsql-only, so map it only for relational providers and ignore it otherwise
-        // (e.g. the InMemory provider used by tests). Production behaviour is unchanged.
+        // GIN index, maintained by the DB and read-only in code. Subject is weighted 'A'
+        // and body 'B' so ts_rank_cd ranks a subject match above a body-only mention. The
+        // tsvector type is Npgsql-only, so map it only for relational providers and ignore
+        // it otherwise (e.g. the InMemory provider used by tests).
         if (Database.IsRelational())
         {
             modelBuilder.Entity<Email>().Property(e => e.SearchVector)
                 .HasColumnType("tsvector")
                 .HasComputedColumnSql(
-                    "to_tsvector('english', coalesce(\"Subject\",'') || ' ' || coalesce(\"BodyText\",''))",
+                    "setweight(to_tsvector('english', coalesce(\"Subject\",'')), 'A') || " +
+                    "setweight(to_tsvector('english', coalesce(\"BodyText\",'')), 'B')",
                     stored: true);
             modelBuilder.Entity<Email>().HasIndex(e => e.SearchVector).HasMethod("GIN");
         }

src/InboxIntel.Infrastructure/Search/SearchService.cs

@@ -77,15 +77,39 @@ public class SearchService : ISearchService
                .ThenByDescending(e => e.SentAtUtc)
             : q.OrderByDescending(e => e.SentAtUtc);
 
-        var items = await ranked
-            .Skip((r.Page - 1) * r.PageSize)
-            .Take(r.PageSize)
-            .Select(e => new EmailSummaryDto(
-                e.Id, e.GmailMessageId, e.Subject, e.Snippet,
-                e.Sender!.Address, e.Sender.DisplayName, e.SentAtUtc,
-                e.IsUnread, e.IsStarred, e.HasAttachments, e.SizeEstimateBytes, e.Category,
-                e.HasListUnsubscribe, e.SupportsOneClickUnsubscribe))
-            .ToListAsync(ct);
+        var paged = ranked.Skip((r.Page - 1) * r.PageSize).Take(r.PageSize);
+
+        // Two unconditional projections (no DB function inside a C# ternary → no doubt about
+        // EF translation). The browse path never touches ts_headline, so it's byte-for-byte
+        // unchanged AND safe under the InMemory test provider.
+        List<EmailSummaryDto> items;
+        if (hasFreeTextQuery)
+        {
+            // "Why this matched": ts_headline body fragment with matched terms wrapped in
+            // U+E000/U+E001 sentinels (safe, non-HTML — the client renders them as escaped
+            // <mark> spans; see EmailSummaryDto).
+            var headlineOpts =
+                $"StartSel={(char)0xE000},StopSel={(char)0xE001},MaxWords=16,MinWords=5,ShortWord=2,HighlightAll=false";
+            items = await paged
+                .Select(e => new EmailSummaryDto(
+                    e.Id, e.GmailMessageId, e.Subject, e.Snippet,
+                    e.Sender!.Address, e.Sender.DisplayName, e.SentAtUtc,
+                    e.IsUnread, e.IsStarred, e.HasAttachments, e.SizeEstimateBytes, e.Category,
+                    e.HasListUnsubscribe, e.SupportsOneClickUnsubscribe,
+                    EF.Functions.WebSearchToTsQuery("english", term).GetResultHeadline("english", e.BodyText ?? "", headlineOpts)))
+                .ToListAsync(ct);
+        }
+        else
+        {
+            items = await paged
+                .Select(e => new EmailSummaryDto(
+                    e.Id, e.GmailMessageId, e.Subject, e.Snippet,
+                    e.Sender!.Address, e.Sender.DisplayName, e.SentAtUtc,
+                    e.IsUnread, e.IsStarred, e.HasAttachments, e.SizeEstimateBytes, e.Category,
+                    e.HasListUnsubscribe, e.SupportsOneClickUnsubscribe,
+                    null))
+                .ToListAsync(ct);
+        }
 
         return new PagedResult<EmailSummaryDto>
         {