K13 — EventGroup and coordinated state

K13 provides a typed EventMask<Enum> and EventGroup<Enum> over static FreeRTOS event-group storage. Wait policy is explicit (any/all) and clear policy is explicit (keep/clear_on_exit). WaitResult retains the snapshot returned by the kernel and evaluates it against the requested policy.

Three workers publish UART, GPIO and APP readiness bits. The coordinator then executes a deterministic state sequence:

wait all, keep          -> snapshot 0x7, current 0x7
clear GPIO              -> clear returns 0x7, current 0x5
wait all, 3 ticks       -> timeout snapshot 0x5, unsatisfied
wait any UART|APP, clear-> snapshot 0x5, current 0x0

Setting UART twice leaves the mask at 0x1, proving an event bit is idempotent state and not an occurrence counter.

Build

make check

Debug

b event_group_debug_checkpoint
p g_coordinator_state_seen
p g_worker_set_result
p g_uart_repeat_mask
p/x g_all_snapshot
p/x g_mask_after_gpio_clear
p/x g_timeout_snapshot
p g_timeout_ticks
p/x g_any_snapshot
p/x g_final_mask
p g_event_group_pass

Scope boundary

Bits coordinate state but carry neither payload nor occurrence count. A clear-on-exit policy can race with other consumers unless designed explicitly. The ISR form of setting bits is not a direct edit of the event group; FreeRTOS defers that operation through the timer service path, which is outside this task-context card.