docs: add product direction plans (import, rationale, availability state)

plans/011-surface-recommendation-rationale.md

@@ -0,0 +1,34 @@
+---
+finding: "Surface recommendation rationale"
+catalog: "Direction"
+impact: "Recommendation results would be more trustworthy if the UI explained why each title was picked."
+base_commit: "0d31d46"
+---
+
+## Effort
+
+M - shape rationale data and render compact UI without changing ranking.
+
+## Risk
+
+LOW - this can be presentation-only if ranking is left unchanged.
+
+## Confidence
+
+HIGH - the recommender computes interpretable signals that are not currently shown.
+
+## Evidence
+
+- `internal/anime/recommendations/profile.go:64-101` builds a taste profile from genres, themes, studios, demographics, airing preference, and recency.
+- `internal/anime/recommendations/types.go:21-28` stores match counts for recommendation candidates.
+- `templates/top_picks.gohtml:22-25` renders only anime cards for Top Picks.
+
+## Resolution Approach
+
+Extend the recommendation result view model with concise, user-readable rationale. Keep ranking unchanged for the first iteration. Examples of acceptable rationale are matched genre/theme/studio badges, “similar to titles in your watchlist,” or “because you watch recent airing shows,” but exact copy should be generated from data already computed by the engine.
+
+Avoid exposing raw scores or overly technical terms. The UI should stay compact enough for card grids and the home carousel. If space is constrained, start with the full `/top-picks` page and leave the home carousel unchanged.
+
+Add recommendation tests that assert rationale is produced for candidates with genre/theme/studio/demographic matches and omitted gracefully when signals are weak. Add template tests or snapshots only if the repo already uses that pattern for similar UI.
+
+Verify with `go test ./internal/anime/... ./templates` and `bunx tsc -p tsconfig.json --noEmit` if any TypeScript changes are needed.