Fix proxy never being used in hotel-page scraper

_proxy_enabled() was checking cfg.get('server') but load_config() returns
{host, port, username, ...} — no 'server' key. Server URL is built by
proxy_util.playwright_proxy(). This meant proxy was silently disabled
and _proxy_kwargs() would also KeyError if called.

- _proxy_enabled() now delegates to proxy_util.is_enabled() (checks host+username)
- _proxy_kwargs() now calls proxy_util.playwright_proxy() with credentials
  embedded in the URL (avoids 14s DataImpulse 407 round-trip)
- _get_context() generates a sticky session_id per context so each worker
  gets a distinct residential IP lane

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

backend/services/scraper_backends/playwright_hotel_page.py

@@ -21,6 +21,7 @@ Rate plan variants per room type (typical):
 import asyncio
 import logging
 import re
+import uuid
 from datetime import date
 from decimal import Decimal
 from typing import List, Optional, Tuple
@@ -29,6 +30,7 @@ from urllib.parse import urlparse
 from playwright.async_api import async_playwright, Browser, BrowserContext, Page
 
 from .base import ScraperBackend, ScraperResult, HotelData, RateData, AvailabilityStatus
+from services import proxy as proxy_util
 
 logger = logging.getLogger(__name__)
 
@@ -161,18 +163,13 @@ class PlaywrightHotelPageBackend(ScraperBackend):
         self._max_requests_per_context = 40
 
     def _proxy_enabled(self) -> bool:
-        return bool(self._proxy_config.get('server'))
+        return proxy_util.is_enabled(self._proxy_config)
 
-    def _proxy_kwargs(self) -> dict:
-        if not self._proxy_enabled():
-            return {}
-        cfg = self._proxy_config
-        proxy = {'server': cfg['server']}
-        if cfg.get('username'):
-            proxy['username'] = cfg['username']
-        if cfg.get('password'):
-            proxy['password'] = cfg['password']
-        return {'proxy': proxy}
+    def _proxy_kwargs(self, session_id: Optional[str] = None) -> dict:
+        # Credentials embedded in URL — separate username/password fields cause
+        # a 407 round-trip that takes ~14s on DataImpulse (see proxy.py comment).
+        proxy = proxy_util.playwright_proxy(self._proxy_config, session_id)
+        return {'proxy': proxy} if proxy else {}
 
     async def _start(self):
         if not self._pw:
@@ -191,16 +188,17 @@ class PlaywrightHotelPageBackend(ScraperBackend):
                     await self._context.close()
                 except Exception:
                     pass
+            session_id = uuid.uuid4().hex[:12] if self._proxy_enabled() else None
             self._context = await self._browser.new_context(
                 user_agent=(
                     'Mozilla/5.0 (Windows NT 10.0; Win64; x64) '
                     'AppleWebKit/537.36 (KHTML, like Gecko) '
                     'Chrome/125.0.0.0 Safari/537.36'
                 ),
-                **self._proxy_kwargs(),
+                **self._proxy_kwargs(session_id),
             )
             self._requests_on_context = 0
-            logger.debug("Opened new browser context" + (" (with proxy)" if self._proxy_enabled() else ""))
+            logger.debug("Opened new browser context" + (f" (proxy session {session_id})" if session_id else ""))
         return self._context
 
     async def _rotate_context(self):