fix: ensure series loaded from DB before NFO scan

- Call _load_series_into_memory() before NFO scan phases to sync DB
  to SeriesApp memory, fixing missing NFO for recently resolved folders
- Add TMDB lookup for series without cached tmdb_id during NFO creation
- Add get_tmdb_client() factory and get_tmdb_image_base_url() helpers
- Fix: use get_tv_show_details instead of deprecated get_series_details
- Fix tests: mock _load_series_into_memory in NFO scan tests

src/server/nfo/tmdb_client.py

@@ -422,3 +422,32 @@ class TMDBClient:
         if expired_keys:
             logger.debug("Removed %d expired negative cache entries", len(expired_keys))
         return len(expired_keys)
+
+
+def get_tmdb_client() -> TMDBClient:
+    """Factory function to create a TMDBClient with settings configuration.
+
+    Returns:
+        TMDBClient instance configured with settings.tmdb_api_key
+
+    Raises:
+        ValueError: If TMDB API key is not configured
+    """
+    from src.config.settings import settings
+
+    if not settings.tmdb_api_key:
+        raise ValueError("TMDB API key is not configured")
+
+    return TMDBClient(api_key=settings.tmdb_api_key)
+
+
+def get_tmdb_image_base_url(tmdb_id: int) -> str:
+    """Get the base URL for TMDB images.
+
+    Args:
+        tmdb_id: TMDB show ID (used for account-specific URLs)
+
+    Returns:
+        Base URL string for TMDB images
+    """
+    return "https://image.tmdb.org/t/p/"