feat: integrate MinIO-backed user filesystem

app-instance/backend/beaver/engine/session/store.py

@@ -12,6 +12,7 @@
 from __future__ import annotations
 
 import json
+import os
 import sqlite3
 import threading
 import time
@@ -110,6 +111,12 @@ END;
 """
 
 
+def _sqlite_journal_mode() -> str:
+    requested = os.getenv("BEAVER_SQLITE_JOURNAL_MODE", "DELETE").strip().upper()
+    allowed = {"DELETE", "TRUNCATE", "PERSIST", "MEMORY", "OFF", "WAL"}
+    return requested if requested in allowed else "DELETE"
+
+
 class SessionStore:
     """SQLite-backed session store."""
 
@@ -119,7 +126,9 @@ class SessionStore:
         self._lock = threading.Lock()
         self._conn = sqlite3.connect(str(self.db_path), check_same_thread=False, isolation_level=None)
         self._conn.row_factory = sqlite3.Row
-        self._conn.execute("PRAGMA journal_mode=WAL")
+        self._conn.execute("PRAGMA mmap_size=0")
+        self._conn.execute("PRAGMA busy_timeout=5000")
+        self._conn.execute(f"PRAGMA journal_mode={_sqlite_journal_mode()}")
         self._conn.execute("PRAGMA foreign_keys=ON")
         self._init_schema()