Add remote browser pages and website sync

Enable managed remote browser custom pages with login autofill and add website sync workflows so external admin surfaces can be handled inside SmartUp.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/app/config.py

@@ -11,8 +11,10 @@ class Settings(BaseSettings):
     tz: str = "Asia/Shanghai"
     # consecutive failures before upstream goes unhealthy
     unhealthy_threshold: int = 3
+    browser_profiles_dir: str = "/app/data/browser-profiles"
+    browser_headless: bool = True
 
-    model_config = {"env_file": ".env", "case_sensitive": False}
+    model_config = {"env_file": ".env", "case_sensitive": False, "extra": "ignore"}
 
 
 @lru_cache