Auto-init DB on dashboard start if file missing

_init_db() creates the schema at startup so /api/db/*
endpoints work immediately without needing a batch run first.

dashboard.py

@@ -33,10 +33,27 @@ _db_conn = None
 _db_lock = threading.Lock()
 
 
+def _init_db(db_path: str) -> None:
+    conn = sqlite3.connect(db_path)
+    conn.execute("PRAGMA journal_mode=WAL")
+    conn.execute("""CREATE TABLE IF NOT EXISTS batch_runs (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        date TEXT NOT NULL, location TEXT NOT NULL, camera_id TEXT NOT NULL,
+        total_entered INTEGER NOT NULL DEFAULT 0,
+        frames_processed INTEGER NOT NULL DEFAULT 0,
+        elapsed_seconds REAL NOT NULL DEFAULT 0.0,
+        stopped_reason TEXT NOT NULL DEFAULT '',
+        source_video TEXT NOT NULL DEFAULT '',
+        generated_at TEXT NOT NULL DEFAULT '',
+        UNIQUE(date, location, camera_id))""")
+    conn.commit()
+    conn.close()
+
+
 def _get_db():
     global _db_conn
     db = app.config["db_path"]
-    if not db or not Path(db).exists():
+    if not db:
         return None
     with _db_lock:
         if _db_conn is None:
@@ -196,6 +213,9 @@ def main():
     app.config["run_date"] = args.date
     app.config["db_path"] = str(Path(args.db).resolve()) if args.db else ""
 
+    if app.config["db_path"]:
+        _init_db(app.config["db_path"])
+
     print(f"[dashboard] http://0.0.0.0:{args.port}  shm={args.shm_dir}  db={args.db}" + (f"  date={args.date}" if args.date else ""))
     app.run(host="0.0.0.0", port=args.port, debug=args.debug, threaded=True)