fix(daemon): send self-compact nudge straight away instead of queueing for Stop

[rogeriochaves]

Problem

The headless auto-compact guard escalates: at 500k/600k/700k it nudges the agent to self-compact, and at 750k it sends /compact directly. The 500/600/700k nudges were queued and only auto-sent when the agent next emitted a Stop hook.

A freshly-resumed or idle session never emits a Stop, so those gentle nudges never fired. Context coasted all the way up to the 750k hard /compact, which then fired on top of whatever prompt landed next (in practice, the morning scheduled nudge) and that prompt was lost — the agent skipped a day's work.

Fix

Paste the self-compact nudge straight into the session when the threshold is crossed, instead of parking it in the queue. Claude Code queues pasted input and runs it after the current turn, so:

• a busy agent still finishes its current turn before self-compacting (graceful), and
• a resumed/idle agent self-compacts immediately, well before its next scheduled prompt arrives.

lastTriggered still ensures each threshold nudges only once; the 750k hard /compact backstop is unchanged. Removed the now-unused enqueueOnce helper.

Tests

Updated the daemon auto-compact test to assert the nudge is pasted straight away (not queued) and not re-sent for the same threshold. Full suite green (197).

[rogeriochaves]

Dropping this. The queued self-compact nudge (fire at next Stop) is the intended behavior: a soft nudge should land at a stop point, and an idle session just rides up to the 750k hard /compact, after which the next prompt arrives post-compaction. The straight-away paste defeated the purpose of the queuePrompt path.