fix: split HTTP connect/read timeouts (Jellyfin build + qBit stats)

Every HTTP client passed an integer timeout to requests, applying the same
value to BOTH connect and read phases. A slow Jellyfin /Items page or qBit
/sync/maindata blew through the 10s read budget → ReadTimeoutError. Split
into a (connect=5s, read=60s default) tuple via shared http_timeout() helper.
The media index build worker uses a 180s read floor. Existing services with
low timeout_seconds benefit from bumping to 60+.

backend/src/media_library_viewer_api/integrations/jellyfin.py

@@ -29,7 +29,7 @@ def test_connection(
     try:
         base_url = str(config.get("base_url") or "")
         api_key = str(secrets.get("api_key") or "")
-        timeout = int(config.get("timeout_seconds") or 10)
+        timeout = int(config.get("timeout_seconds") or 60)
         client = JellyfinClient(base_url, api_key, timeout=timeout)
         users = client.users()
         return TestResult(ok=True, detail="Connected to Jellyfin.", evidence=f"{len(users)} users")
@@ -49,7 +49,7 @@ class JellyfinConfig(ServiceConfigBase):
 
     base_url: ServiceBaseUrl
     user_id: str = ""
-    timeout_seconds: int = 10
+    timeout_seconds: int = 60
     jellyseerr_url: str = ""
     jellyseerr_api_key: str = ""