Add tests that exercise the ACTUAL running loop with cancel_event
signaling, not just AdapterState math in isolation.
Test cases:
- Test 1: Cadence decrease (60->30) wakes loop immediately
- Test 2: Cadence increase (10->20) extends wait correctly
- Test 3: Enable/disable/enable with gap > cadence polls immediately
- Test 4: Enable/disable/enable with gap < cadence waits
These tests verify the cancel_event mechanism properly interrupts
the sleeping loop when config changes occur via _on_config_change.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
