fix(backend): make default schema consistent in db.py

The search_path setup at module init defaulted to "platform" when no
schema was in DATABASE_URL, but get_database_schema() defaults to
"public". This caused a mismatch where search_path used platform
schema but raw SQL queries used public schema.

Changed search_path setup to also default to "public" for consistency.

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

autogpt_platform/backend/backend/data/db.py

@@ -40,10 +40,10 @@ if POOL_TIMEOUT:
 
 # Add public schema to search_path for pgvector type access
 # The vector extension is in public schema, but search_path is determined by schema parameter
-# Extract the schema from DATABASE_URL or default to 'platform'
+# Extract the schema from DATABASE_URL or default to 'public' (matching get_database_schema())
 parsed_url = urlparse(DATABASE_URL)
 url_params = dict(parse_qsl(parsed_url.query))
-db_schema = url_params.get("schema", "platform")
+db_schema = url_params.get("schema", "public")
 # Build search_path, avoiding duplicates if db_schema is already 'public'
 search_path_schemas = list(
     dict.fromkeys([db_schema, "public"])