fix: C-01 WebRTC policy value, C-02 scoped taskkill, C-04 preflight race, E-11 socket timeout, E-27 ban test dedup, full audit doc

proxy_chain_manager/browser_launcher.py

@@ -279,6 +279,9 @@ class BrowserSession:
         return True, f"Firefox started ({mode}, pid {pid})."
 
     def stop(self, dispose: bool = False) -> tuple[bool, str]:
+        # Capture our PID before clearing the handle
+        launched_pid: int | None = self._proc.pid if self._proc else None
+
         # Terminate the Popen handle if still alive
         if self._proc and self._proc.poll() is None:
             try:
@@ -292,17 +295,19 @@ class BrowserSession:
             finally:
                 self._proc = None
 
-        # Also kill any remaining firefox.exe processes (handles the
-        # detached-child case where the parent already exited naturally)
-        try:
-            subprocess.run(
-                ["taskkill", "/F", "/IM", "firefox.exe"],
-                capture_output=True,
-                timeout=10,
-                creationflags=getattr(subprocess, "CREATE_NO_WINDOW", 0x08000000),
-            )
-        except Exception:
-            pass
+        # Kill only the process tree we spawned (handles the detached-child
+        # case where the launcher process already exited naturally).
+        # /T kills the entire child tree; /PID scopes to our PID only.
+        if launched_pid is not None:
+            try:
+                subprocess.run(
+                    ["taskkill", "/F", "/T", "/PID", str(launched_pid)],
+                    capture_output=True,
+                    timeout=10,
+                    creationflags=getattr(subprocess, "CREATE_NO_WINDOW", 0x08000000),
+                )
+            except Exception:
+                pass
 
         self._proc = None
         if dispose and self._profile_path and self._profile_path.exists():