Scraper: force-reset endpoint + watchdog to prevent stuck lock

Root cause: threading.Lock held indefinitely when Playwright browser
hangs inside run_in_executor (finally never fires from the async side).

Fixes:
- _acquire_scrape_lock/_release_scrape_lock track monotonic timestamp
- POST /competitors/scrape/reset force-releases the lock and marks any
  running batch as interrupted (queue rows stay intact for retry)
- GET /competitors/status now includes lock_held_seconds
- APScheduler watchdog job every 30 min auto-releases if held >3h
- Settings → Scraper Proxy tab shows live lock status (green/amber)
  with a Force Reset button requiring confirmation

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/api/competitors.py

@@ -79,6 +79,7 @@ class ScraperStatusResponse(BaseModel):
     location_configured: bool
     location_name: Optional[str]
     last_scrape: Optional[dict]
+    lock_held_seconds: Optional[int] = None
 
 
 # ============================================
@@ -133,12 +134,16 @@ async def get_scraper_status(
             'error_message': last_scrape_row.error_message,
         }
 
+    from services.booking_scraper import get_lock_status
+    lock = get_lock_status()
+
     return ScraperStatusResponse(
         enabled=config.get('booking_scraper_enabled', 'false') == 'true',
         backend=config.get('booking_scraper_backend', 'playwright_local'),
         location_configured=location_row is not None,
         location_name=location_row.location_name if location_row else None,
-        last_scrape=last_scrape
+        last_scrape=last_scrape,
+        lock_held_seconds=lock["held_seconds"],
     )
 
 
@@ -408,8 +413,8 @@ async def trigger_manual_scrape(
     # Best-effort early 409: the background task re-acquires the lock and will
     # no-op (logging "another scrape is running") if it loses a millisecond-
     # window race, so no double-run can slip through here.
-    from services.booking_scraper import SCRAPE_LOCK
-    if SCRAPE_LOCK.locked():
+    from services.booking_scraper import get_lock_status
+    if get_lock_status()["locked"]:
         raise HTTPException(status_code=409, detail="A scrape is already running. Try again when it finishes.")
 
     # Start background task
@@ -423,6 +428,25 @@ async def trigger_manual_scrape(
     }
 
 
+@router.post("/scrape/reset")
+async def reset_scraper(
+    db: AsyncSession = Depends(get_db),
+    current_user: dict = Depends(get_current_user),
+):
+    """Force-release the scrape lock and mark any stuck running batches as interrupted.
+    Use when the scraper is stuck and the 409 won't clear on its own."""
+    if not (current_user.get('is_admin') or 'manage_scraper' in (current_user.get('caps') or [])):
+        raise HTTPException(status_code=403, detail="manage_scraper capability required")
+
+    from services.booking_scraper import force_reset_scraper
+    sync_db = SyncSessionLocal()
+    try:
+        result = force_reset_scraper(sync_db)
+    finally:
+        sync_db.close()
+    return result
+
+
 # ============================================
 # HOTELS MANAGEMENT
 # ============================================