feat: login MAS OIDC end-to-end (issue 0147)

Backend Go:
- MatrixService with Login/GetSession/Logout bindings
- Uses 3 registry helpers via go.work:
  - mas_oidc_loopback_go_infra (PKCE flow)
  - keyring_token_store_go_infra (SO keychain)
  - matrix_client_init_go_infra (mautrix client)
- whoami helper to discover user_id+device_id pre-init

Frontend React+Vite+TS:
- Mantine v7 + @tabler/icons-react
- LoginScreen with 'Sign in with Matrix' button
- HomeScreen with profile card + logout
- Dark theme violet accent
- @mantine/notifications wired

Wails config:
- Switched to pnpm (workspace: protocol)
- Bindings auto-generated for MatrixService
- 1280x800 default window

Build: 68MB linux/amd64 binary in build/bin/

frontend/package.json

@@ -1,7 +1,7 @@
 {
-  "name": "frontend",
+  "name": "matrix_client_pc-frontend",
   "private": true,
-  "version": "0.0.0",
+  "version": "0.1.0",
   "type": "module",
   "scripts": {
     "dev": "vite",
@@ -9,14 +9,18 @@
     "preview": "vite preview"
   },
   "dependencies": {
-    "react": "^18.2.0",
-    "react-dom": "^18.2.0"
+    "@mantine/core": "^7.13.0",
+    "@mantine/hooks": "^7.13.0",
+    "@mantine/notifications": "^7.13.0",
+    "@tabler/icons-react": "^3.19.0",
+    "react": "^18.3.1",
+    "react-dom": "^18.3.1"
   },
   "devDependencies": {
-    "@types/react": "^18.0.17",
-    "@types/react-dom": "^18.0.6",
-    "@vitejs/plugin-react": "^2.0.1",
-    "typescript": "^4.6.4",
-    "vite": "^3.0.7"
+    "@types/react": "^18.3.10",
+    "@types/react-dom": "^18.3.0",
+    "@vitejs/plugin-react": "^4.3.1",
+    "typescript": "^5.6.2",
+    "vite": "^5.4.8"
   }
-}
+}