P0-fix: plugin migrations use migration engine (crm_migration) instead of API engine (crm_api)

- main.py: registry.initialize(get_migration_engine()) instead of get_engine()
- main.py: plugin migrations run via get_migration_session_factory() not async_session()
- registry.py: upgrade_plugin, install_plugin, uninstall_plugin all use migration session for DDL
- db/__init__.py: get_migration_engine() raises RuntimeError if MIGRATION_DATABASE_URL missing (no fallback)
- Fixes fresh-install failure: crm_api has no DDL rights, plugin migrations need crm_migration

app/plugins/registry.py

@@ -494,9 +494,13 @@ class PluginRegistry:
             f"Running migrations to update."
         )
 
-        # Re-run migrations to apply any new migration files
+        # Re-run migrations to apply any new migration files — use migration engine (crm_migration) for DDL
         if plugin.manifest.migrations:
-            await self.migration_runner.run_all_migrations(db, name, plugin.manifest.migrations)
+            from app.core.db import get_migration_session_factory
+            mig_factory = get_migration_session_factory()
+            async with mig_factory() as mig_db:
+                await self.migration_runner.run_all_migrations(mig_db, name, plugin.manifest.migrations)
+                await mig_db.commit()
 
         # Update DB version to match manifest
         record.version = manifest_version
@@ -548,9 +552,13 @@ class PluginRegistry:
         # Check dependencies are installed
         await self._check_dependencies_installed(db, name)
 
-        # Run migrations
+        # Run migrations — use migration engine (crm_migration) for DDL
         if plugin.manifest.migrations:
-            await self.migration_runner.run_all_migrations(db, name, plugin.manifest.migrations)
+            from app.core.db import get_migration_session_factory
+            mig_factory = get_migration_session_factory()
+            async with mig_factory() as mig_db:
+                await self.migration_runner.run_all_migrations(mig_db, name, plugin.manifest.migrations)
+                await mig_db.commit()
 
         # Call on_install hook
         await plugin.on_install(db, self._container)
@@ -741,10 +749,14 @@ class PluginRegistry:
         # Call on_uninstall hook
         await plugin.on_uninstall(db, self._container)
 
-        # Optionally drop plugin tables
+        # Optionally drop plugin tables — use migration engine (crm_migration) for DDL
         dropped_tables: list[str] = []
         if remove_data:
-            dropped_tables = await self.migration_runner.drop_plugin_tables(db, name)
+            from app.core.db import get_migration_session_factory
+            mig_factory = get_migration_session_factory()
+            async with mig_factory() as mig_db:
+                dropped_tables = await self.migration_runner.drop_plugin_tables(mig_db, name)
+                await mig_db.commit()
 
         # Remove DB record
         await db.delete(record)