Address review feedback: deduplicate query_type, clean unused imports, fix defaults

- Remove duplicate detect_query_type from query.py (divergent 5-type version);
  canonical 7-type version lives in query_type.py
- Fix reddit.py import to use query_type.detect_query_type
- Clean unused STOPWORDS/SYNONYMS/tokenize imports from youtube_yt, instagram,
  tiktok, scrapecreators_x, bird_x after relevance consolidation
- Fix _relevance_filter default from 0.7 to 0.0 (items without relevance
  should not silently pass the filter)
- Remove --dateafter from yt-dlp (returns 0 results for evergreen topics)
- Remove restrictSearchableAttributes from HN search (misses Ask/Show HN)
- Lower HN points filter from >5 to >2 (avoids filtering niche posts)
- Add error logging to select_openai_model HTTP failures
- Remove mise.toml and internal planning doc from repo
- Update module docstrings to describe current purpose, not migration history
- Update tests to import from canonical relevance module

scripts/lib/models.py

@@ -53,6 +53,10 @@ def is_search_capable_model(model_id: str) -> bool:
     Includes mini variants (same structured extraction quality, lower cost).
     Excludes: nano (no web_search), gpt-4o-mini (no domain filtering),
     chat/codex/pro/preview/turbo/search (specialized variants).
+
+    Note: gpt-5 with reasoning effort="minimal" does NOT support web_search
+    (per OpenAI docs). We never set reasoning params — our usage is pure
+    tool invocation + JSON extraction — so gpt-5 is safe to include here.
     """
     model_lower = model_id.lower()