fix: Query external APIs when database entry has no dateadded

The system was skipping external API calls when a database entry existed
but had no useful data (dateadded: None). This caused movies to get minimal
NFO files even when digital release dates were available.

Added condition to should_query logic: also query APIs when we have an
existing database entry but no dateadded value.

This fixes the Flow (2019) issue where it should fetch digital release
dates from TMDB/OMDB but was returning "no_valid_date_source" instead.

nfoguard.py

@@ -1001,7 +1001,8 @@ class MovieProcessor:
             should_query = (
                 config.movie_poll_mode == "always" or
                 (config.movie_poll_mode == "if_missing" and not existing) or
-                (config.movie_poll_mode == "if_missing" and existing and existing.get("source") == "file:mtime")
+                (config.movie_poll_mode == "if_missing" and existing and existing.get("source") == "file:mtime") or
+                (config.movie_poll_mode == "if_missing" and existing and not existing.get("dateadded"))
             )
             
             # Use existing movie date decision logic