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/cv-search-data/Migrations/20260524145702_AddLanguageToJobSearchEntities.cs

@@ -1,4 +1,5 @@
 using Microsoft.EntityFrameworkCore.Migrations;
+using CvSearch.Data;
 
 #nullable disable
 
@@ -12,7 +13,7 @@ namespace CvSearch.Data.Migrations
         {
             migrationBuilder.AddColumn<string>(
                 name: "Language",
-                schema: "cvSearch",
+                schema: MigrationConstants.SchemaName,
                 table: "JobSearchTokens",
                 type: "nvarchar(8)",
                 maxLength: 8,
@@ -21,7 +22,7 @@ namespace CvSearch.Data.Migrations
 
             migrationBuilder.AddColumn<string>(
                 name: "Language",
-                schema: "cvSearch",
+                schema: MigrationConstants.SchemaName,
                 table: "JobSearchSessions",
                 type: "nvarchar(8)",
                 maxLength: 8,
@@ -34,12 +35,12 @@ namespace CvSearch.Data.Migrations
         {
             migrationBuilder.DropColumn(
                 name: "Language",
-                schema: "cvSearch",
+                schema: MigrationConstants.SchemaName,
                 table: "JobSearchTokens");
 
             migrationBuilder.DropColumn(
                 name: "Language",
-                schema: "cvSearch",
+                schema: MigrationConstants.SchemaName,
                 table: "JobSearchSessions");
         }
     }