951bba7a21
Root cause of 'I clicked many times but only got two screenshots':
finishing/pausing a session called backend.stop(), which cancelled every
in-flight frame request to null. Clicks whose PNG had not finished
encoding yet were then dropped — only the first few survived.
Fixes:
- Stream backend now *drains* on stop: it stops accepting new requests but
keeps the worker alive until frames already selected for queued clicks
finish encoding. stop({ immediate: true }) keeps the old abandon-now
behavior for an unhealthy worker.
- Two-stage worker reply: a fast 'frame-selected' ack pins the pairing and
proves liveness; the slow PNG payload follows. A slow encode (seconds on
software-rendered hosts) is no longer mistaken for a dead worker, which
had been forcing the post-click fresh-shot fallback (late screenshots).
- Queued clicks carry their guide id and are stored even if the session
ends while they wait in the queue.
- The tray gesture that stops a session is discarded by matching its
recorded screen position, not a time window — a fast workflow click near
the stop is no longer collateral damage. (Replaces the earlier grace
window, which dropped whole bursts.)
- A click on a display with no ready stream resolves null so the caller
fresh-shots the correct monitor instead of returning another screen.
- STEPFORGE_CAPTURE_LOG=1 prints one line per click decision; the
second-instance handler now surfaces the running window instead of
exiting silently.
- Self-test gains a fast-burst-then-finish scenario (8/8 saved) and the
marker/coordinate checks remain at 0.00% offset.
Tests: 133 unit + all repo checks passing.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>