feat: simplify journal connection via WebSocket upgrade

Refactor the journal server to run over WebSockets on the existing
HTTP server instead of a separate MQTT TCP port. This removes the need
for a separate port configuration and simplifies the connection flow
by auto-connecting to the current host.

- Remove `--mqtt-port` CLI option
- Attach Aedes broker to the HTTP server via WebSocket upgrade
- Update UI to remove manual broker URL and player name inputs
- Add "Content Source" access from the sidebar
- Update JournalPanel to auto-connect to the local server

package-lock.json

@@ -29,6 +29,7 @@
         "solid-js": "^1.9.3",
         "three": "^0.183.2",
         "three-3mf-exporter": "^45.1.0",
+        "ws": "^8.21.0",
         "yarn-spinner-loader": "^0.1.0",
         "zod": "^4.4.3"
       },
@@ -46,6 +47,7 @@
         "@types/jest": "^30.0.0",
         "@types/js-yaml": "^4.0.9",
         "@types/node": "^22.19.13",
+        "@types/ws": "^8.18.1",
         "husky": "^9.1.7",
         "jest": "^29.7.0",
         "jest-environment-jsdom": "^29.7.0",
@@ -10693,9 +10695,9 @@
       }
     },
     "node_modules/ws": {
-      "version": "8.20.0",
-      "resolved": "https://registry.npmjs.org/ws/-/ws-8.20.0.tgz",
-      "integrity": "sha512-sAt8BhgNbzCtgGbt2OxmpuryO63ZoDk/sqaB/znQm94T4fCEsy/yV+7CdC1kJhOU9lboAEU7R3kquuycDoibVA==",
+      "version": "8.21.0",
+      "resolved": "https://registry.npmjs.org/ws/-/ws-8.21.0.tgz",
+      "integrity": "sha512-Vsp28b7DRcimFQvrqu2Wek3z1iYxDCWqHYB8Qsnk/S4RfaCQzPGPyBNuVjJV3cd6UiKtUtp6sNM77gWvzcCH+g==",
       "license": "MIT",
       "engines": {
         "node": ">=10.0.0"