fix(parser): handle None return from raw_parser to avoid AttributeError (#992)

When raw_parser fails to parse non-episodic resources (movies, collections),
it returns None. Add guard clause in title_parser to skip these gracefully
instead of crashing on attribute access. Downgrade log level from error to
info since this is expected behavior.

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

backend/src/module/parser/title_parser.py

@@ -68,6 +68,8 @@ class TitleParser:
                 episode = Episode(**episode_dict)
             else:
                 episode = raw_parser(raw)
+                if episode is None:
+                    return None
 
             titles = {
                 "zh": episode.title_zh,