fix(pool): dispose per-worker completion futures on shutdown/reload — no leaked cross-thread triggers (#93)

[EdmondDantes]

Problem

http_server_start_pool() owns the completion futures returned by pool->submit_internal() (one per worker) but never disposed them. Each future's shared-state cross-thread wakeup trigger (a uv_async on the parent reactor) stayed armed after shutdown:

• debug: the scheduler's loop-alive assert (scheduler.c — "The event loop must be stopped") aborts on the parent thread's finalize;
• release: a uv_async handle leaks per worker (async: leftover libuv handle).

reload() leaked the same way, once per rotation.

The reason it was never seen: every existing pool test exits via SIGKILL, so the process dies before the parent reactor finalizes. Async\graceful_shutdown() is the real clean path, and it tripped this.

Fix

Store each worker_evt in pool_worker_ctx_t.done_event and dispose it:

• in start_pool's cleanup: (covers every exit path, including the gotos);
• in reload() for the retired cohort, so they don't accumulate across reloads.

Disposal is race-safe against a still-running worker via the paired fix true-async/php-async#182 (remote_future_dispose now severs the producer under the shared-state mutex before closing the trigger). The shared st->cb carries a no-op dispose so freeing a disposed future's callback vector never touches the embedded, shared callback.

Tests

• 055-pool-graceful-shutdown — pool serves, graceful_shutdown(), start() returns clean.
• 056-pool-shutdown-timeout-zero — setShutdownTimeout(0), immediate quiesce.
• 057-pool-reload-then-shutdown — reload() then graceful_shutdown(), both cohorts reaped.

All green ×5, no flake (was a race).

Dependency

⚠️ Requires true-async/php-async#182. CI here stays red until that lands in the pinned async build.

[github-actions]

Coverage

Total lines: 74.29% → 75.44% (+1.16 pp)

File	Baseline	Current	Δ	Touched
src/core/http_connection_tls.c	73.67%	73.39%	-0.28 pp
src/http3/http3_callbacks.c	61.64%	61.21%	-0.43 pp
src/http3/http3_listener.c	66.35%	66.19%	-0.16 pp
src/http_server_class.c	52.02%	61.90%	+9.88 pp	●
src/http_server_config.c	89.83%	90.73%	+0.90 pp