feat(companion): add Electron presentation layer with React UI, IPC handlers, and automation POC

vite.config.electron.ts

@@ -0,0 +1,19 @@
+import { defineConfig } from 'vite';
+import react from '@vitejs/plugin-react';
+import { resolve } from 'path';
+
+export default defineConfig({
+  plugins: [react()],
+  base: './',
+  root: '.',
+  build: {
+    outDir: 'dist/renderer',
+    emptyOutDir: true,
+    rollupOptions: {
+      input: resolve(__dirname, 'src/apps/companion/renderer/index.html')
+    }
+  },
+  server: {
+    port: 5173
+  }
+});