v0.21.0 — desktop app: Settings + Memory/Skills/Schedule/Tasks

The Chimera Desktop app (from v0.20.0) is now a full control surface — not just chat. A left icon-rail navigates dedicated screens, each a live view over the real managers.

Added

• ⚙️ Settings — models, cost mode, cascade, API keys (per provider, always masked to a last-4 hint — the raw key is never returned), memory backend, cache, sandbox, and the API bearer token. Writes go to .env through a strict allowlist (no arbitrary-key injection).
• 🧠 Memory — browse / search / add facts, a persona flag, and unverified badges on tainted memory.
• ✨ Skills — learned skills with status + uses/wins/rate, plus approve / retire and a retire? hint.
• ⏰ Schedule — scheduled cron jobs with an enable toggle and delete.
• ▦ Tasks — projects with HITL approve/deny on high-risk milestone steps, plus the kanban board.

Every read and the HITL approve/deny writes are LLM-free (they reuse MemoryManager / SkillStore / CronStore / the project orchestrator's checkpoint methods without ever chaining a run); token-spending work stays on the chat/solve paths. The endpoints live under /api/*; the bearer token guards the mutations when set.

Backend: chimera/api/features.py + config_api.py. Frontend: apps/desktop (Vite + React + TS + Tailwind). Built + smoke-tested live against a real store. Gate: 1480 passed / 4 skipped, mypy + ruff green.

Upgrade: `pip install --upgrade 'chimera-agent[desktop]'` then `npm --prefix apps/desktop install && npm --prefix apps/desktop run build && chimera app`