v0.5.3's one-shot skip only blocked a single auto-drain, but a Stop emits
multiple idle events (message_complete + status idle); the second one still
drained one queued message and flipped the button back to running. Replace
the one-shot skip with a sticky queueDrainPaused flag: Stop pauses all
auto-drains until the user sends their next message (which clears it and
fires immediately, ahead of the queue). The queue then resumes FIFO on the
next idle. Bumps desktop app to 0.5.4 with release notes.
Tested: tsc --noEmit; Vitest chatStore 94 passed (incl. multi-idle stop /
priority message / queue resume); browser end-to-end (Stop keeps button at
Run with queue intact, priority send immediate, queue resumes); Windows x64
NSIS package + package-smoke PASS.
Scope-risk: narrow
Confidence: high
