Harden score endpoint with resilient fallback and sqlite race/lock handling

backend/db.py

@@ -6,15 +6,17 @@ DB_PATH = BASE_DIR / "data" / "staysense.db"
 
 
 def get_conn() -> sqlite3.Connection:
-    conn = sqlite3.connect(DB_PATH)
+    conn = sqlite3.connect(DB_PATH, timeout=10)
     conn.row_factory = sqlite3.Row
     conn.execute("PRAGMA foreign_keys = ON")
+    conn.execute("PRAGMA busy_timeout = 10000")
     return conn
 
 
 def init_db() -> None:
     DB_PATH.parent.mkdir(parents=True, exist_ok=True)
     with get_conn() as conn:
+        conn.execute("PRAGMA journal_mode = WAL")
         conn.executescript(
             """
             CREATE TABLE IF NOT EXISTS spot (