feat: brew-log & palate loop — tasting capture + cross-bag recipe pre-correction

[Leolebleis]

Summary

Closes the tasting feedback loop. Capture how a brew tasted (conversationally, structured), then use it to pre-correct future recipes: "you got a Geisha natural → you tend to find those sour → here's a recipe started finer/tighter."

Built on the existing journal/ + bags/ contexts. Stays in sqlite — no new deps, no ANN/vector infra (it's exact weighted-KNN at personal scale).

What's in it

• Bag enriched with varietal / process / altitude_masl (the queryable bean dimensions).
• JournalEntry gains signed tasting axes acidity/bitterness/body/sweetness/strength (−2…+2, 0=balanced) + flavor_tags + a bean_dimensions_snapshot frozen at log time.
• journal/palate.py — a weighted-KNN read-model (tendency_for): finds similar past brews, similarity-weights their axes, returns a tendency + confidence + neighbours. Graceful degradation when history is sparse.
• MCP tools log_tasting (capture; snapshots bean dims) and query_palate (the lookup /brew calls).
• db.add_missing_columns — idempotent additive migration for the already-populated DB; live-run in the lifespan.
• Skills: new /brew-log (capture + tasting coaching, fault→lever from the Coffee Compass, BWT-water rule) and a /brew palate pre-flight that pre-corrects from history. Plugin 0.2.0 → 0.3.1.

Quality

• TDD throughout, subagent-driven (fresh implementer + review per task).
• Final holistic review (opus) → fix-then-merge; all findings actioned (import order, proper typing dropping ty:ignores, direct attr access, migration-CHECK doc).
• /simplify pass → data-driven bag update builder, jsonify in query_palate, walrus in the palate axis loop.
• 389 tests pass, ruff --no-cache clean, ruff format clean, ty clean.

Known scope

Palate learning is conversational-only this phase: structured capture flows through /brew-log. The web rating toast / REST PATCH /journal/{id} send a rating only (no axes), so they deliberately don't feed the KNN. A structured web tasting form + its learning contribution lands with the web-UI work (alongside the parked Phase 2b embeddings). Documented in the spec.

Follow-ups (not in this PR)

• JournalService.update / repo.update are now production-dead (superseded by record_tasting) — candidate for removal once the old tests adopt record_tasting.
• Parent raspberrypi repo: bump the brew submodule pointer after merge.