fix(sec): update npm deps to resolve npm audit warnings

pin brace-expansion to 5.0.8
update concurrently to 10.0.4
update electron-builder to 26.15.3
update eslint to 10.8.0
update eslint-plugin-perfectionist to 5.10.0
update @assistant-ui/react to 0.15.0
update @assistant-ui/react-streamdown to 0.3.8
update radix-ui to 1.6.7
update react-router-dom to react-router@8.3.0 - react-router-dom is no longer a standalone package, it just reexports react-router
remove @radix-ui/react-slot: we import this from `radix-ui`
remove eslint-plugin-react: we imported it, but never actually used it!

package.json

@@ -41,7 +41,8 @@
   "overrides": {
     "lodash": "4.18.1",
     "yauzl": "^3.3.1",
-    "protobufjs": "^8.7.1"
+    "protobufjs": "^8.7.1",
+    "brace-expansion": "5.0.8"
   },
   "engines": {
     "node": ">=20.0.0"