fix(storage): use dynamic schema_getter in PostgreSQLFileStorage for multi-tenant (#440)

PostgreSQLFileStorage was initialized once at startup with a static
schema value. Since get_current_schema() returns the default schema at
init time, multi-tenant requests always queried the wrong schema,
causing "relation file_storage does not exist" errors.

Replace static schema with schema_getter callable (same pattern used
by BrokerTaskBackend since #208) so the schema is resolved dynamically
per-request via contextvars.

hindsight-api/hindsight_api/engine/memory_engine.py

@@ -1366,7 +1366,7 @@ class MemoryEngine(MemoryEngineInterface):
         self._file_storage = create_file_storage(
             storage_type=config.file_storage_type,
             pool_getter=lambda: self._pool,
-            schema=get_current_schema() if get_current_schema() != config.database_schema else None,
+            schema_getter=get_current_schema,
         )
         logger.debug(f"File storage initialized ({config.file_storage_type})")
 

hindsight-api/hindsight_api/engine/storage/__init__.py

@@ -12,6 +12,7 @@ def create_file_storage(
     storage_type: str,
     pool_getter: Callable | None = None,
     schema: str | None = None,
+    schema_getter: Callable | None = None,
     **kwargs,
 ) -> FileStorage:
     """
@@ -20,7 +21,8 @@ def create_file_storage(
     Args:
         storage_type: "native" (PostgreSQL BYTEA) or "s3" (S3-compatible object storage)
         pool_getter: Database pool getter (required for native)
-        schema: Database schema (for native multi-tenant)
+        schema: Static database schema (for native single-tenant)
+        schema_getter: Callable returning current schema at query time (for native multi-tenant)
         **kwargs: Additional args passed to storage backend
 
     Returns:
@@ -32,7 +34,7 @@ def create_file_storage(
     if storage_type == "native":
         if not pool_getter:
             raise ValueError("pool_getter required for native (PostgreSQL) storage")
-        return PostgreSQLFileStorage(pool_getter=pool_getter, schema=schema)
+        return PostgreSQLFileStorage(pool_getter=pool_getter, schema=schema, schema_getter=schema_getter)
     elif storage_type == "s3":
         from ...config import get_config
         from .s3 import S3FileStorage

hindsight-api/hindsight_api/engine/storage/postgresql.py

@@ -40,16 +40,30 @@ class PostgreSQLFileStorage(FileStorage):
     For production/scale, consider S3FileStorage instead.
     """
 
-    def __init__(self, pool_getter: Callable[[], "asyncpg.Pool"], schema: str | None = None):
+    def __init__(
+        self,
+        pool_getter: Callable[[], "asyncpg.Pool"],
+        schema: str | None = None,
+        schema_getter: Callable[[], str] | None = None,
+    ):
         """
         Initialize PostgreSQL file storage.
 
         Args:
             pool_getter: Function that returns asyncpg connection pool
-            schema: Database schema (for multi-tenant support)
+            schema: Static database schema (fallback for single-tenant / tests)
+            schema_getter: Callable returning current schema at query time (for multi-tenant)
         """
         self._pool_getter = pool_getter
-        self._schema = schema
+        self._static_schema = schema
+        self._schema_getter = schema_getter
+
+    @property
+    def _schema(self) -> str | None:
+        """Resolve schema dynamically per-request when schema_getter is provided."""
+        if self._schema_getter:
+            return self._schema_getter()
+        return self._static_schema
 
     async def store(
         self,