feat(pgsql): support vector and PostGIS indexes with extensions

* Add handling for pgvector and PostGIS extensions in migration scripts
* Implement operator class and storage parameters for vector indexes
* Update tests to validate new index behaviors and extension creation

pkg/writers/pgsql/templates.go

@@ -140,6 +140,9 @@ type CreateIndexData struct {
 	Columns    string
 	Unique     bool
 	Concurrent bool
+	// StorageParameters holds access-method parameters rendered as WITH (...),
+	// e.g. "lists = 100" for ivfflat or "m = 16, ef_construction = 64" for hnsw.
+	StorageParameters string
 }
 
 // CreateForeignKeyData contains data for create foreign key template