Customizable nav lanes: pin moods / topics / discovery tags

Readers can now choose which quick-access lanes sit above the feed; "Today"
stays pinned. The pool (goodnews/lanes.py, served at /api/lanes) is one source
of truth over three lane kinds the feed already renders: moods, primary topics,
and high-volume Discovery tags. Selection lives in the existing prefs blob
(localStorage + /api/prefs sync); the filter parser ignores the new `lanes`
field, so it rides along harmlessly. Default = today's moods, unchanged.

Food/Space stay grouping tags rather than primary topics (per review): `space`
already existed; added `food` to the Mind & Craft family so the classifier
assigns it, and seeded the Food lane by re-tagging the two food sources.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitignore

@@ -5,3 +5,4 @@ __pycache__/
 data/*.sqlite3
 data/*.sqlite3-*
 
+logs/