fix: Configure EF Core migration history tables with schema-qualified names

Each DbContext now explicitly configures its migration history table to use
the schema-qualified name pattern [schemaName].[_Migrations]:
- [cvMatcher].[_Migrations] for CvMatcherDbContext
- [emailApi].[_Migrations] for EmailApiDbContext
- [cvSearch].[_Migrations] for CvSearchDbContext
- [rag].[_Migrations] for RagDbContext
- [myAi].[_Migrations] for MyAiDbContext

This is done via OnConfiguring() with UseSqlServer().MigrationsHistoryTable(name, schema).

Removed incorrect rename migrations that were created due to misunderstanding
of the proper EF Core configuration approach.

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

Apis/cv-search-data/Data/CvSearchDbContext.cs

@@ -14,6 +14,13 @@ public sealed class CvSearchDbContext : DbContext
     public DbSet<JobSearchSessionEntity> JobSearchSessions => Set<JobSearchSessionEntity>();
     public DbSet<JobSearchResultEntity> JobSearchResults => Set<JobSearchResultEntity>();
 
+    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
+    {
+        base.OnConfiguring(optionsBuilder);
+        // Configure migration history table to use schema-qualified name: [cvSearch].[_Migrations]
+        optionsBuilder.UseSqlServer(x => x.MigrationsHistoryTable(MigrationTableName, SchemaName));
+    }
+
     protected override void OnModelCreating(ModelBuilder modelBuilder)
     {
         modelBuilder.HasDefaultSchema(SchemaName);