ci / rust (push) Failing after 2m15s
Add an orthogonal activity dimension to sessions, inferred entirely from
structured tmux/`/proc` state — no PTY byte-stream parsing, no work on the
attach hot path.
Protocol: `ActivityState` enum (Active/Idle/AwaitingInput) + three additive,
serde-defaulted `Session` fields (`foreground`, `activity`, `last_activity_at`)
so the snapshot/diff flow stays forward-compatible with older daemons.
Detection (piggybacks the existing ~2s liveness tick, no new timer):
- foreground command via `tmux list-panes -F '#{pane_pid} #{pane_current_command}
#{pane_tty}'`;
- quiescence from a per-`PtyBridge` last-read `Instant`, bumped in `run_reader`;
- AwaitingInput via best-effort `/proc` walk to the deepest descendant: state
`S` + a non-timer `wchan` + an stdio fd on the pane tty. (`/proc/pid/syscall`
is ptrace-gated and unreadable for own sessions, so `wchan` distinguishes a
blocking read from a plain `sleep`.)
- combine: recent output → Active; else input-blocked → AwaitingInput; else
Idle. Emit `SessionUpdated` only on (activity, foreground) change — no diff
storms at steady state.
`maestro list` gains an ACTIVITY column and shows the live foreground. Pure
combine/parse logic is unit-tested; an e2e asserts `cat` → AwaitingInput and
`sleep` → Idle with correct foreground against real tmux.
Closes #18
Closes #8
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>