revert: Back to simple MigrateAsync - it's already idempotent

MigrateAsync is smart enough to:
- Create DB if it doesn't exist
- Apply only pending migrations
- Skip if DB is up to date

The orphaned CMS.mdf files were cleaned from SQL Server.

src/CMSMicroservice.Infrastructure/Persistence/ApplicationDbContextInitialiser.cs

@@ -23,25 +23,7 @@ public  class ApplicationDbContextInitialiser
         {
             if (_context.Database.IsSqlServer())
             {
-                // Use EnsureCreated for initial setup, then apply migrations
-                // EnsureCreated is idempotent - safe to call multiple times
-                var created = await _context.Database.EnsureCreatedAsync();
-                
-                if (!created)
-                {
-                    // Database exists, check for pending migrations
-                    _logger.LogInformation("Database already exists, checking for migrations...");
-                    var pending = await _context.Database.GetPendingMigrationsAsync();
-                    if (pending.Any())
-                    {
-                        _logger.LogInformation("Applying {Count} pending migrations", pending.Count());
-                        await _context.Database.MigrateAsync();
-                    }
-                }
-                else
-                {
-                    _logger.LogInformation("Database created successfully");
-                }
+                await _context.Database.MigrateAsync();
             }
         }
         catch (Exception ex)