feat: implement websocket-stream for journal server

Integrate `websocket-stream` to handle MQTT broker upgrades in the
CLI and add granular connection status tracking to the UI.

- Add `websocket-stream` dependency
- Update CLI to use `websocket-stream` for socket upgrades
- Enhance `journalStream` store with `connectionStatus` and
  `connectionError` states
- Add visual connection status indicators to `App` and `JournalPanel`

package.json

@@ -52,6 +52,7 @@
     "solid-js": "^1.9.3",
     "three": "^0.183.2",
     "three-3mf-exporter": "^45.1.0",
+    "websocket-stream": "^5.5.2",
     "ws": "^8.21.0",
     "yarn-spinner-loader": "^0.1.0",
     "zod": "^4.4.3"