refactor(data): rename email-api-data to email-data for consistent naming

- Rename project folder Apis/email-api-data → Apis/email-data
- Rename csproj file: email-api-data.csproj → email-data.csproj
- Update csproj properties: AssemblyName and RootNamespace (email-data, Email.Data)
- Update C# namespaces: EmailApi.Data → Email.Data across all email-data files
- Update project references in api.csproj and email-api.csproj
- Update migration assembly references in api/Program.cs and email-api/Program.cs
- Update cv-search-job references to use email-data project and Email.Data namespace
- Update solution file to reference new email-data project path
- Remove hardcoded schema name from SmtpEmailDispatcher, use template service instead

This maintains consistency with other data project naming convention (no service-type suffix).
All tests passing, build succeeds.

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

Apis/email-data/MigrationConstants.cs

@@ -0,0 +1,11 @@
+namespace Email.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 = "email";
+    public const string MigrationTableName = "_Migrations";
+}