Retry page load timeouts: treat as blocks, bump max retries to 4

DataImpulse endpoints are intermittently broken — some return EOF after
CONNECT immediately, others work fine. DNS round-robins between them so
the same request can fail 3× then succeed on the 4th. Timeouts were
returning blocked=False and silently failing with no retry. Now treated
as retryable blocks (with context rotation) so a fresh endpoint is tried.
Max retries 2→4 (5 total attempts) to give enough chances to land a
working DataImpulse endpoint.

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

backend/services/scraper_backends/playwright_hotel_page.py

@@ -298,7 +298,11 @@ class PlaywrightHotelPageBackend(ScraperBackend):
                 logger.warning(f"goto timeout for {hotel_url} {check_in}: {e}")
 
             if not page_loaded:
-                return ScraperResult(success=False, blocked=False, error_message='page load timeout')
+                # Treat as a retryable block — DataImpulse endpoints are intermittently
+                # broken (EOF after CONNECT); rotating to a fresh context hits a different
+                # endpoint and usually succeeds within 1-2 retries.
+                await self._rotate_context()
+                return ScraperResult(success=False, blocked=True, block_reason='page load timeout')
 
             # Wait for the room table (prices render via JS after DOM)
             room_table_appeared = False