[EdmondDantes]

Fixes #426.

A refused gRPC request body (HTTP/2 and HTTP/3, in-thread and under the HTTP/3 reactor pool) ended with a bare stream reset; curl read ENHANCE_YOUR_CALM and no grpc-status. It now ends with grpc-status: 8 (RESOURCE_EXHAUSTED; 13 for a 500 refusal) and a grpc-message, HTTP 200, trailers-only, followed by #412's clean reset.

• h2_judge_refusal / h3_judge_refusal: gRPC is judged like any stream; WebSocket keeps the error reset; a gRPC response still being streamed keeps it too.
• grpc_call_ensure_refusal_status (H2 dispose, H3 dispose, reactor answer): status from refused_status whether the handler failed or not; a status the handler set is kept with its own message.
• Reactor: decided by req->grpc_mode (no worker has classified the call yet); grpc_call_init_response, status trailers promoted into the headers.
• readMessage() throws the refusal's HttpException at entry and when a refusal ends its wait; the H2/H3 body upgrade does nothing on a refused request. Before, a handler that caught the refusal and read again parked for good.

Critic on the design (unsound, fixed) and on the diff (sound with remarks, all taken: grpc/022 lacked TRUE_ASYNC_SERVER_REACTOR_POOL=1; the wait loop threw RuntimeException 0; no test of a handler's own status).

Evidence (ZTS DEBUG, local): grpc/020-025 fail on main and pass 10 of 10; full phpt 635 passed, 2 skipped, 0 failed; cmocka 24 of 24. 023/024 time the upload in PHP (_grpc_h2_upload.inc, proc_open without a shell) so they run on Windows; not run on Windows locally.

Not covered: gRPC-Web over HTTP/1.1 keeps the HTTP/1 413 path. On the reactor a request with a gRPC content type but no gRPC handler gets the gRPC answer (the reactor has no handler map; the cumulative-cap waiver already keys on the content type).

[github-actions]

Coverage

Total lines: 85.89% → 85.91% (+0.01 pp)

File	Baseline	Current	Δ	Touched
src/grpc/grpc_call.c	100.00%	100.00%	+0.00 pp	●
src/http2/http2_session.c	91.63%	91.63%	+0.00 pp	●
src/http2/http2_strategy.c	86.15%	86.18%	+0.03 pp	●
src/http3/http3_callbacks.c	86.88%	86.87%	-0.01 pp	●
src/http3/http3_connection.c	86.39%	86.45%	+0.07 pp
src/http3/http3_dispatch.c	90.94%	91.08%	+0.13 pp	●
src/http3/http3_io.c	89.09%	89.68%	+0.59 pp
src/http_request.c	90.10%	90.00%	-0.10 pp	●