feat: add release notes overlay with Markdown rendering

- Replace truncated plaintext release notes with full-screen overlay
  rendered via `marked` library
- Server reconnection does a hard page reload instead of custom event

server/package.json

@@ -21,6 +21,7 @@
   },
   "dependencies": {
     "chart.js": "^4.5.1",
-    "elkjs": "^0.11.1"
+    "elkjs": "^0.11.1",
+    "marked": "^17.0.5"
   }
 }