chore: strip UTF-8 BOM from EF-generated migration files

The .editorconfig charset=utf-8 rule (added with the CI format gate) flags the BOM
that 'dotnet ef migrations' writes into generated files, failing the format check on
develop itself and thus on every PR. De-BOM all tracked source files so the gate passes.

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

src/InboxIntel.Infrastructure/Migrations/20260630140733_InitialCreate.Designer.cs

@@ -1,4 +1,4 @@
-// <auto-generated />
+// <auto-generated />
 using System;
 using InboxIntel.Infrastructure.Persistence;
 using Microsoft.EntityFrameworkCore;

src/InboxIntel.Infrastructure/Migrations/20260630200946_AddUserDigestFields.Designer.cs

@@ -1,4 +1,4 @@
-// <auto-generated />
+// <auto-generated />
 using System;
 using InboxIntel.Infrastructure.Persistence;
 using Microsoft.EntityFrameworkCore;

src/InboxIntel.Infrastructure/Migrations/20260630201607_AddUnsubscribeConfidence.Designer.cs

@@ -1,4 +1,4 @@
-// <auto-generated />
+// <auto-generated />
 using System;
 using InboxIntel.Infrastructure.Persistence;
 using Microsoft.EntityFrameworkCore;

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

@@ -1,4 +1,4 @@
-// <auto-generated />
+// <auto-generated />
 using System;
 using InboxIntel.Infrastructure.Persistence;
 using Microsoft.EntityFrameworkCore;

src/InboxIntel.Infrastructure/Migrations/20260701203001_EnablePgTrgm.Designer.cs

@@ -1,4 +1,4 @@
-// <auto-generated />
+// <auto-generated />
 using System;
 using InboxIntel.Infrastructure.Persistence;
 using Microsoft.EntityFrameworkCore;

src/InboxIntel.Infrastructure/Migrations/20260701235112_TrigramIndexesSenderDomain.Designer.cs

@@ -1,4 +1,4 @@
-// <auto-generated />
+// <auto-generated />
 using System;
 using InboxIntel.Infrastructure.Persistence;
 using Microsoft.EntityFrameworkCore;

src/InboxIntel.Infrastructure/Migrations/20260702002304_AddEmbeddingColumn.Designer.cs

@@ -1,4 +1,4 @@
-// <auto-generated />
+// <auto-generated />
 using System;
 using InboxIntel.Infrastructure.Persistence;
 using Microsoft.EntityFrameworkCore;

src/InboxIntel.Infrastructure/Migrations/20260702152850_FeatureFlagsAndUserSettings.Designer.cs

@@ -1,4 +1,4 @@
-// <auto-generated />
+// <auto-generated />
 using System;
 using InboxIntel.Infrastructure.Persistence;
 using Microsoft.EntityFrameworkCore;

src/InboxIntel.Infrastructure/Migrations/20260702152850_FeatureFlagsAndUserSettings.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using Microsoft.EntityFrameworkCore.Migrations;
 
 #nullable disable

src/InboxIntel.Infrastructure/Migrations/AppDbContextModelSnapshot.cs

@@ -1,4 +1,4 @@
-// <auto-generated />
+// <auto-generated />
 using System;
 using InboxIntel.Infrastructure.Persistence;
 using Microsoft.EntityFrameworkCore;