Stop test_svc stub HTTP orphans after SIGKILL

Why: the agent stub left python http.server children when tearDown
SIGKILL'd the bash parent, leaking ports 1880x into recover/identity
suites that share the same range.
Evidence: local suite re-run pending after this fix.
Impact: stub HTTP child exits when ppid changes (same as recover stub).
Refs: .task/feature-svc-rdm-ui-gate.md

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/test_svc.py

@@ -62,8 +62,10 @@ case "${1:-}" in
     trap 'kill "$child" 2>/dev/null; exit 0' TERM INT
     # GET/HEAD 一律 200（健康探测语义与 http.server 等价）；PUT /api/* 捕获头与
     # 请求体到 trace/put.txt 供播种断言（settings 播种验证，2026-10-11）。
+    # HTTP 子进程轮询 ppid：父进程被 SIGKILL 后自行退出，避免与 recover 套件
+    # 共用 1880x 端口时泄漏占用（与 test_svc_recover 桩同规）。
     python3 - "$port" "$host" "$trace_dir" <<'PYSRV' >/dev/null 2>&1 &
-import sys
+import os, sys, threading, time
 from http.server import BaseHTTPRequestHandler, HTTPServer
 port, host, trace = int(sys.argv[1]), sys.argv[2], sys.argv[3]
 class H(BaseHTTPRequestHandler):
@@ -85,7 +87,20 @@ class H(BaseHTTPRequestHandler):
         self._ok()
     def log_message(self, *args):
         pass
-HTTPServer((host, port), H).serve_forever()
+ppid = os.getppid()
+def watch():
+    while True:
+        try:
+            if os.getppid() != ppid:
+                os._exit(0)
+        except Exception:
+            os._exit(0)
+        time.sleep(0.3)
+threading.Thread(target=watch, daemon=True).start()
+try:
+    HTTPServer((host, port), H).serve_forever()
+except Exception:
+    os._exit(1)
 PYSRV
     child=$!
     wait "$child"