fix(email): preserve draft send identity

Persist and export each draft's idempotency UUID so refresh and edits cannot create a fresh delivery identity. Add reversible provider-specific migration SQL.

JobTrackerApi/Controllers/BackupController.cs

@@ -100,6 +100,7 @@ namespace JobTrackerApi.Controllers
                     draft.Subject,
                     draft.BodyText,
                     draft.ThreadId,
+                    draft.ClientRequestId,
                     draft.Revision,
                     draft.CreatedAtUtc,
                     draft.UpdatedAtUtc))

JobTrackerApi/Controllers/EmailDraftsController.cs

@@ -25,6 +25,7 @@ public sealed class EmailDraftsController(
         string Subject,
         string BodyText,
         string? ThreadId,
+        string ClientRequestId,
         long Revision,
         DateTime CreatedAtUtc,
         DateTime UpdatedAtUtc);
@@ -41,15 +42,17 @@ public sealed class EmailDraftsController(
 
     [HttpGet]
     public async Task<ActionResult<IReadOnlyList<DraftDto>>> List(
-        [FromQuery] int jobApplicationId,
+        [FromQuery] int? jobApplicationId,
         CancellationToken cancellationToken)
     {
         var ownerUserId = GetOwnerUserId();
         if (ownerUserId is null) return Unauthorized();
-        if (jobApplicationId <= 0) return BadRequest("A valid job application is required.");
+        if (jobApplicationId is <= 0) return BadRequest("A valid job application is required.");
 
-        return Ok(await db.EmailDrafts.AsNoTracking()
-            .Where(draft => draft.OwnerUserId == ownerUserId && draft.JobApplicationId == jobApplicationId)
+        var query = db.EmailDrafts.AsNoTracking().Where(draft => draft.OwnerUserId == ownerUserId);
+        if (jobApplicationId.HasValue)
+            query = query.Where(draft => draft.JobApplicationId == jobApplicationId.Value);
+        return Ok(await query
             .OrderByDescending(draft => draft.UpdatedAtUtc)
             .Select(draft => new DraftDto(
                 draft.Id,
@@ -59,6 +62,7 @@ public sealed class EmailDraftsController(
                 draft.Subject,
                 draft.BodyText,
                 draft.ThreadId,
+                draft.ClientRequestId,
                 draft.Revision,
                 draft.CreatedAtUtc,
                 draft.UpdatedAtUtc))
@@ -103,6 +107,7 @@ public sealed class EmailDraftsController(
             Subject = subject,
             BodyText = bodyText,
             ThreadId = threadId,
+            ClientRequestId = Guid.NewGuid().ToString("D"),
             Revision = 1,
             CreatedAtUtc = now,
             UpdatedAtUtc = now,
@@ -193,6 +198,7 @@ public sealed class EmailDraftsController(
         draft.Subject,
         draft.BodyText,
         draft.ThreadId,
+        draft.ClientRequestId,
         draft.Revision,
         draft.CreatedAtUtc,
         draft.UpdatedAtUtc);

JobTrackerApi/Data/JobTrackerContext.cs

@@ -288,6 +288,7 @@ namespace JobTrackerApi.Data
         modelBuilder.Entity<EmailDraft>().Property(x => x.To).HasMaxLength(320);
         modelBuilder.Entity<EmailDraft>().Property(x => x.Subject).HasMaxLength(998);
         modelBuilder.Entity<EmailDraft>().Property(x => x.ThreadId).HasMaxLength(512);
+        modelBuilder.Entity<EmailDraft>().Property(x => x.ClientRequestId).HasMaxLength(128);
         modelBuilder.Entity<EmailDraft>()
             .HasIndex(x => new { x.OwnerUserId, x.JobApplicationId, x.UpdatedAtUtc });
         modelBuilder.Entity<EmailDraft>()

JobTrackerApi/Migrations/20260810080858_AddEmailDraftClientRequestId.cs

@@ -0,0 +1,39 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace JobTrackerApi.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddEmailDraftClientRequestId : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            if (ActiveProvider.Contains("MySql", StringComparison.OrdinalIgnoreCase))
+            {
+                migrationBuilder.Sql("""
+                    ALTER TABLE `EmailDrafts`
+                    ADD `ClientRequestId` varchar(128) NOT NULL DEFAULT '';
+                    """);
+                return;
+            }
+
+            migrationBuilder.AddColumn<string>(
+                name: "ClientRequestId",
+                table: "EmailDrafts",
+                type: "TEXT",
+                maxLength: 128,
+                nullable: false,
+                defaultValue: "");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "ClientRequestId",
+                table: "EmailDrafts");
+        }
+    }
+}

JobTrackerApi/Migrations/JobTrackerContextModelSnapshot.cs

@@ -1108,6 +1108,11 @@ namespace JobTrackerApi.Migrations
                         .IsRequired()
                         .HasColumnType("TEXT");
 
+                    b.Property<string>("ClientRequestId")
+                        .IsRequired()
+                        .HasMaxLength(128)
+                        .HasColumnType("TEXT");
+
                     b.Property<DateTime>("CreatedAtUtc")
                         .HasColumnType("TEXT");
 

JobTrackerApi/Models/EmailDraft.cs

@@ -11,6 +11,7 @@ public sealed class EmailDraft
     public string Subject { get; set; } = string.Empty;
     public string BodyText { get; set; } = string.Empty;
     public string? ThreadId { get; set; }
+    public string ClientRequestId { get; set; } = string.Empty;
     public long Revision { get; set; } = 1;
     public DateTime CreatedAtUtc { get; set; }
     public DateTime UpdatedAtUtc { get; set; }
@@ -24,6 +25,7 @@ public sealed record EmailDraftExport(
     string Subject,
     string BodyText,
     string? ThreadId,
+    string ClientRequestId,
     long Revision,
     DateTime CreatedAtUtc,
     DateTime UpdatedAtUtc);

JobTrackerApi/Services/DailyExportHostedService.cs

@@ -88,6 +88,7 @@ public sealed class DailyExportHostedService(
                     draft.Subject,
                     draft.BodyText,
                     draft.ThreadId,
+                    draft.ClientRequestId,
                     draft.Revision,
                     draft.CreatedAtUtc,
                     draft.UpdatedAtUtc))