Notify on IDLE→ARMED and ARMED→PRIMED so the user gets staged warnings
before FIRE. If atm run starts mid-cycle on dark_green/dark_red, synth
a catchup arm so the prime alert still fires (audit tagged catchup:true).
If it starts on light_green/light_red, emit one late_start warn and skip
the FSM feed — FIRE already passed.
Extracted _handle_tick() as a pure helper (takes fsm + duck-typed
notifier/audit Protocols) so the dispatch is unit-testable without
mocking FanoutNotifier. 9 new tests cover arm, prime, refresh silence,
catchup synth-arm (+ audit), and late-start on both directions.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Also: calibrate._sample_rgb now snaps to the most-saturated pixel within 15px
of the click, so rough clicks still pick up the dot's pure colour. Default
dot-colour tolerance bumped 30→60 to absorb anti-aliasing.
Test fixture _SAMPLED_RGB recomputed for the new 36/49 dilution (was 24/49
when sampling at the trailing edge).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
