Plan document for issue #2 — the three-way PIN hash mismatch across
CLI, events FSM, and web arm/disarm. Proposes canonicalizing on
PBKDF2-SHA256 via alerts/pin and [security] pin_hash, deprecating
[system] arm_pin_hash, and wiring web arm/disarm through MQTT to the
FSM so the web buttons actually transition state.
Nine tasks, TDD throughout. No code changes in this commit.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>