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

tests/test_models.py

@@ -30,6 +30,12 @@ class TestParseVersion(unittest.TestCase):
 
 class TestIsSearchCapableModel(unittest.TestCase):
     def test_gpt5_is_capable(self):
+        """gpt-5 supports web_search when reasoning is not set to 'minimal'.
+
+        Per OpenAI docs, gpt-5 with reasoning effort="minimal" does NOT
+        support web_search. We never set reasoning params (our usage is
+        tool invocation + JSON extraction only), so gpt-5 is safe here.
+        """
         self.assertTrue(models.is_search_capable_model("gpt-5"))
 
     def test_gpt52_is_capable(self):