[EdmondDantes]

Closes #346.

A handler's $server->stop() on a reactor-pool worker stopped that worker's clone and left its request inbox in the worker registry, so the reactors kept routing HTTP/3 requests to it, and the clone ran them after the stop, with isRunning() false, in the scope start() was draining. do_stop now unpublishes the inbox on every stop. start() fences the reactors after its wait (the retire the pool path already ran), and waits out a retire the pool coroutine still has in flight instead of freeing the server under it. The bailout and failed-wait exits, which cannot fence, unpublish before the free, and start() does not publish when a stop already waits.

The second case of the issue, a clone started again with the old inbox, is unreachable: the pool loads a fresh clone per worker run and starts it once, and a start() from the clone's own handler throws before the inbox is published.

Evidence.

• h3/079 (requests after a handler's stop): on main 6 to 10 of 16 answered STOPPED, 3 runs of 3; passes with the fix.
• h3/080 (requests sent while the stopping handler holds its thread for 1 s): on main 6 to 7 of 16 answered STOPPED, 3 runs of 3; passes with the fix, and checks that answers arrive inside the window.
• Mutants: dropping the unpublish in do_stop fails h3/080 (2 runs of 2 over the 19 local pool tests). Dropping the fence in start() passes all of them: it covers a dispatch that loaded the inbox just before the unpublish, which no test widens.
• Local suite -j4: 522 of 525 run passed, 25 skipped. The 3 failures, h1/062 to h1/064, fail on main the same way: the local PHP binary was built on 2026-09-26, before Pause a stopped listen event instead of accepting through it (#305) php-async#306, which they need.

[github-actions]

Coverage

Total lines: 83.91% → 83.97% (+0.06 pp)

File	Baseline	Current	Δ	Touched
src/core/worker_registry.c	77.91%	79.07%	+1.16 pp
src/http1/http_parser.c	87.58%	87.98%	+0.41 pp
src/http3/http3_callbacks.c	86.28%	86.38%	+0.10 pp
src/http3/http3_dispatch.c	88.08%	88.30%	+0.22 pp
src/http3/http3_listener.c	76.76%	78.56%	+1.80 pp
src/http_server_class.c	76.02%	75.99%	-0.03 pp	●
src/websocket/ws_session.c	89.71%	89.89%	+0.18 pp