Move RAG repository from rag-api to rag-data — consolidate data layer ownership

- Move IRagRepository, EfRagRepository, and VectorSerializer from rag-api/Data to rag-data/Repositories
- Add rag-api-models ProjectReference to rag-data.csproj for model type availability
- Delete rag-api/Data folder (no longer needed; all data access is now in rag-data)
- This aligns RAG with email-api and other services: all data code in the data project

Pattern: rag-api (API logic) → rag-data (repository, EF entities, migrations)

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

Apis/email-api-data/EmailApiDbContext.cs

@@ -5,8 +5,8 @@ namespace EmailApi.Data;
 
 public sealed class EmailApiDbContext : DbContext
 {
-    public const string SchemaName = "emailApi";
-    public const string MigrationTableName = "_Migrations";
+    public const string SchemaName = MigrationConstants.SchemaName;
+    public const string MigrationTableName = MigrationConstants.MigrationTableName;
 
     public EmailApiDbContext(DbContextOptions<EmailApiDbContext> options) : base(options) { }
 

Apis/email-api-data/MigrationConstants.cs

@@ -0,0 +1,11 @@
+namespace EmailApi.Data;
+
+/// <summary>
+/// Schema constants used by EmailApiDbContext and migrations.
+/// Centralized to avoid hardcoded strings and ensure consistency.
+/// </summary>
+public static class MigrationConstants
+{
+    public const string SchemaName = "emailApi";
+    public const string MigrationTableName = "_Migrations";
+}

Apis/email-api-data/Migrations/20260528100000_CreateEmailTemplates.cs

@@ -1,5 +1,6 @@
 using System;
 using Microsoft.EntityFrameworkCore.Migrations;
+using EmailApi.Data;
 
 #nullable disable
 
@@ -11,11 +12,11 @@ namespace EmailApi.Data.Migrations
         /// <inheritdoc />
         protected override void Up(MigrationBuilder migrationBuilder)
         {
-            migrationBuilder.EnsureSchema(name: "emailApi");
+            migrationBuilder.EnsureSchema(name: MigrationConstants.SchemaName);
 
             migrationBuilder.CreateTable(
                 name: "EmailTemplates",
-                schema: "emailApi",
+                schema: MigrationConstants.SchemaName,
                 columns: table => new
                 {
                     Key = table.Column<string>(type: "nvarchar(128)", maxLength: 128, nullable: false),
@@ -39,7 +40,7 @@ namespace EmailApi.Data.Migrations
                 => m.InsertData("EmailTemplates",
                     ["Key", "Language", "Value", "Description", "OperatorCopy"],
                     [key, lang, value, description, operatorCopy],
-                    "emailApi");
+                    MigrationConstants.SchemaName);
 
             // ── HTML shell (no operator copy — these are layout fragments, not addressable emails) ──
             Row("email.html-shell.start", "*",

Apis/email-api-data/Migrations/20260528130652_SeedEmailTemplates.cs

@@ -1,4 +1,5 @@
 using Microsoft.EntityFrameworkCore.Migrations;
+using EmailApi.Data;
 
 #nullable disable
 
@@ -31,7 +32,7 @@ namespace EmailApi.Data.Migrations
                 => m.InsertData("EmailTemplates",
                     ["Key", "Language", "Value", "Description", "OperatorCopy"],
                     [key, lang, value, description, operatorCopy],
-                    "emailApi");
+                    MigrationConstants.SchemaName);
 
             // ── HTML shell (no operator copy — these are layout fragments, not addressable emails) ──
             Row("email.html-shell.start", "*",