v1.3.0 — home-screen endpoints: /api/profile + /api/spin

Two REST endpoints powering the extension's new logged-in home screen (see ext-v0.3.0). Both are served from the KV-cached collection/wantlist aggregates — zero Discogs API calls once warm, so casual panel opens never touch the user's rate budget.

• GET /api/profile — the shelf as a profile: collection/wantlist sizes, added-this-month, dominant styles (top 5 with % shares), genres, decades, top labels, vinyl/CD/other format split, 5 most recently added, and the known-moods list
• GET /api/spin?mood= — "what to spin tonight": 1–3 rating-weighted picks from the user's own collection matching a mood, sampled from the strongest candidates so repeat calls vary; honest 422s for unknown moods or empty matches

No MCP-head changes. Deployed to the hosted instance.

Full Changelog: v1.2.0...v1.3.0