Fork-owned, host-tested MQTT bridge lifecycle state machine and the narrow
dependency seam to drive it deterministically, plus the cross-core ownership
model. This is the Phase 4 "ownership and teardown test seams" safety net that
must land before the Phase 5 cooperative-shutdown refactor.
- src/helpers/MQTTLifecycle.h: pure state machine
(Stopped->Starting->Running->StopRequested->Stopping->Stopped) + injected
Ops seam (clock / task / resource owner / OTA barrier) + Coordinator with a
bounded stop timeout. No Arduino/FreeRTOS/WiFi deps.
- test/test_mqtt_lifecycle/: 18 GoogleTest cases covering the phase's teardown
matrix (stop during every activity, callback timing, duplicate/early stop,
restart, timeout fallback, no-access-after-release) and the OTA-barrier
scenarios.
- MQTT_OWNERSHIP.md: one owner per mutable runtime domain, current cross-core
hazards with file:line references, target primitives, and Phase-0-pending
(hardware-characterization) items.
- STABILITY_TESTABILITY_HANDOFF.md: Phase 4 status and verified premise
refinements.
Scope: MQTTBridge.cpp is intentionally untouched. The production rewiring
(plain-data snapshot publication, volatile-handshake replacement, cooperative
shutdown) is deferred to Phase 5.