A game-HUD-style debug overlay (FPS-counter for sessions) that surfaces the
daemon-inferred fields from #18 — activity, foreground, idle time, status — on
the active session, live off the existing events WS. Lets us validate the
inferred data before designing any "real" UI, and stays useful as a permanent
debugging tool.
- Off by default; toggled via Ctrl+Shift+D (persisted in localStorage) or `?hud`
in dev (debug.ts).
- Fixed bottom-right overlay, pointer-events:none so it never blocks the
terminal; activity value is color-coded (active/awaiting/idle).
- Generic: renders every non-client-owned Session field, so a new daemon-derived
field (#19 `detail`, later metrics) surfaces with no overlay change. Idle time
re-renders on a 1s ticker; values update on SessionUpdated.
- Pure consumer-side: no daemon/protocol/registry changes. The `?mock` fixture
seeds varied activity so the HUD can be reviewed without a daemon.
Closes#20
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
