fix(docker+brain): make container Chrome search work, harden, improve toggle

Addresses review findings on the dockerized stack:
- Container Chrome search was dead: add --remote-debugging-port + a non-default
  --user-data-dir (Chrome 136+ refuses CDP on the default profile), add the
  playwright dep (browse-search.mjs connectOverCDP) with browser download
  skipped, and connect to 127.0.0.1 not "localhost" (container localhost -> ::1
  while Chrome binds IPv4). Verified: browse-search returns real results.
- Broadcast toggle reliability: always offer setBroadcast in screen-share mode
  (the embedding/keyword router dropped it for non-English utterances) and make
  its description force a tool call. "방송 꺼줘"->stop now 5/5; no false triggers.
- Stop the broadcast on voice leave (no orphaned stream).
- Security: bind VNC/noVNC to loopback by default (VNC_BIND override) and the
  bridge to the container loopback (BRIDGE_HOST=127.0.0.1), not published.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/jarvis/tools/builtin/set_broadcast.py

@@ -26,10 +26,12 @@ class SetBroadcastTool(Tool):
     @property
     def description(self) -> str:
         return (
-            "Start or stop the live screen-share broadcast (Go-Live / showing your "
-            "screen on the call). Use when the user asks to turn the broadcast or "
-            "screen on or off (show/hide your screen, go live, stop streaming). "
-            "Only available in screen-share mode."
+            "Control the live screen-share broadcast (Go-Live). You MUST call this "
+            "tool — do not just reply in words — whenever the user asks to turn the "
+            "broadcast or screen ON or OFF: start/begin/turn on/show your screen/go "
+            "live -> action='start'; stop/end/turn off/hide your screen/stop "
+            "streaming -> action='stop'. Saying you did it without calling this tool "
+            "does nothing. Only available in screen-share mode."
         )
 
     @property