Implements the architecture change from ai_prompts/prompt3.md:
- New app/click-frames.js: shared timestamped frame ring + strict
click-to-frame pairing (never a frame whose grab started after the
click); legacy slack behavior kept behind capture.strictClickFrames=false.
- New stream capture backend (app/stream-backend.js + hidden worker
window): per-display desktop media streams sampled into ring buffers
and PNG-encoded entirely off the main process, so click delivery is
never starved by capture work. Auto-degrades to the legacy in-process
frame loop when streams cannot start or the worker stops answering.
- Clicks are paired with their frame at event time (eager pairing in
enqueueClickCapture); only the storing is serialized, so slow encodes
cannot skew later clicks in a fast burst.
- Linux watcher: restored event-time root coordinates from
xinput test-xi2 and merge raw/regular twin events structurally.
- Replaced the 40ms time debounce with source-aware duplicate
suppression: fast legitimate clicks are never dropped.
- New app/coords.js: physical-to-DIP conversion with multi-monitor and
scale-factor handling; Windows keeps screenToDipPoint.
- STEPFORGE_CLICK_SELFTEST end-to-end hook: 3/3 clicks become steps via
the stream backend with 0.00% marker offset on this host.
- Tests rewritten/added: strict selection, coords, stream backend,
Linux coordinate parsing, twin merge, burst clicking (126 passing).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Iisyourdad