feat(usage-queue): at-limit toggle button + timed simulation demo mode

[aterrylu]

What

Follow-up to the usage-queue feature (#232) — refines the overlay control based on live UX review, and adds a timed simulation mode so the auto-Enter can be watched firing on its own.

Button → at-limit toggle

• Appears only when you're at the usage cap. At normal usage there's no button; it surfaces as a timely call-to-action exactly when you've run out. Driven by a new capped field on GET /api/usage-queue, computed fresh from usage (via exported evaluateCap) so the control can show before anything is armed — independent of the watcher's armed-only blocked.
• Clear on/off switch — yellow border when off, green when on, sliding toggle. Solid background in both states (no translucency), constant 1.5px border.
• Intent copy — Auto-Enter when limit resets + Type in the terminal to queue (off) / Sends in ~2h13m (on). Spells out both halves: it auto-presses Enter at reset, and you queue by typing in the terminal yourself.
• Hardcoded width so the differing on/off subtitle never resizes the bar; role="switch" for accessibility.

Dev simulation: timed reset

• POST /api/usage-queue/_simulate?state=capped&resetInSec=N caps now and auto-clears after N seconds, firing any armed pane via the server's own countdown — so you can arm a pane and watch the auto-Enter fire with no second call. Extracted applySimulatedClear() keeps the timed transition testable. Still gated behind AUTONOMOS_ENABLE_USAGE_SIMULATION.

Testing

• Button: visibility gating (nothing rendered when not capped), off/on switch states, ETA copy, toggle click.
• Hook: capped wiring, optimistic toggle + rollback.
• Server: resetInSec parsing (set / ignored-for-non-capped / ignored-invalid), applySimulatedClear flips to cleared.
• Real-spawn integration (CI-gated): arms a pane over the API, sets capped&resetInSec=2, and asserts a real claude auto-submits when the countdown elapses. ✅ Verified passing locally.
• Full suite green: server + 253 dashboard, Biome + tsc clean.

Notes

• All UX iterated live with Terry on a dev server (final: at-limit toggle, yellow/green, 270px width).
• No ADR — this refines the already-recorded ADR-042 (usage queue) without changing its architecture.

🤖 Generated with Claude Code

https://claude.ai/code/session_01UpGRD3fxgWmCKyp9nZtrQs

[nox-0x]

Approving — the at-limit visibility gate, the toggle UX rework, and the timed-reset simulation control all hang together cleanly, with the new evaluateCap correctly separating stateless visibility from the watcher's hysteresis-smoothed blocked.

Notes worth a follow-up (none blocking):

• GET /api/usage-queue is now async and awaits getRateLimits() on every poll. The scanner's 60s cache absorbs most of it, but a slow claude.ai call can now stall a status response that used to be sync.
• applySimulatedClear() builds its 'cleared' override with DEFAULT_RESET_SEC (2h13m) in the future — harmless because util=2 makes evaluateCap return capped:false, but the stale reset hint is mildly weird.
• Minor comment rot in UsageQueueButton.tsx: the Switch comment says 'amber track' (it's GREEN), and the border comment says '2px' (it's 1.5px).