fix(tests): live_gui fixture kills stale process on port 8999 before spawn

The fixture detected stale processes on port 8999 but only issued a soft btn_reset POST (which doesn't reset the provider). When a previous batch left a sloppy.py subprocess running, the new subprocess failed to bind port 8999 and the wait loop connected to the stale process instead, leading to cross-batch state pollution (e.g., test_change_provider_via_hook seeing current_provider='gemini' after setting 'anthropic').

Fix: when port 8999 is found LISTENING, parse netstat -ano for the PID, taskkill /F /PID it, sleep 1s, then proceed with the fresh subprocess.Popen.

Verified: tests/test_conftest_watchdog.py 3/3 still pass (the watchdog from e1c8730f is independent of this fix).

tests/conftest.py

@@ -356,15 +356,30 @@ def live_gui() -> Generator[tuple[subprocess.Popen, str], None, None]:
   else:
    os.symlink(src_assets, temp_workspace / "assets")
  
- # Check if already running (shouldn't be)
+ # Check if already running (shouldn't be). If stale, kill the old process
+ # before spawning a new one — otherwise the new subprocess fails to bind
+ # port 8999 and the wait loop connects to the stale process instead,
+ # leading to state pollution across batches.
  try:
   resp = requests.get("http://127.0.0.1:8999/status", timeout=0.5)
   if resp.status_code == 200:
-   print("[Fixture] WARNING: Hook Server already up on port 8999. Test state might be polluted.")
-   # Optionally try to reset it
-   try: requests.post("http://127.0.0.1:8999/api/gui", json={"action": "click", "item": "btn_reset"}, timeout=1)
-   except: pass
- except: pass
+   print("[Fixture] WARNING: Hook Server already up on port 8999. Killing stale process...")
+   netstat = subprocess.run(["netstat", "-ano"], capture_output=True, text=True, timeout=5)
+   stale_pids: set[int] = set()
+   for line in netstat.stdout.splitlines():
+    if ":8999" in line and "LISTENING" in line:
+     parts = line.split()
+     if parts:
+      try: stale_pids.add(int(parts[-1]))
+      except ValueError: pass
+   for pid in stale_pids:
+    try:
+     subprocess.run(["taskkill", "/F", "/PID", str(pid)], capture_output=True, timeout=5)
+     print(f"[Fixture] Killed stale PID {pid}")
+    except Exception: pass
+   time.sleep(1.0)
+   print("[Fixture] Proceeding with fresh sloppy.py spawn")
+ except Exception: pass
 
  print(f"\n[Fixture] Starting {gui_script} --enable-test-hooks in {temp_workspace}...")
  os.makedirs("logs", exist_ok=True)