feat: Phase 1 Foundation & Dashboard implementation

- Core infrastructure: Zustand store, API client with mock fallback
- Mode detection: Port 8080 (kiosk) / 9090 (remote)
- Dashboard components: RainfallCard, ClockDisplay, CommStatus
- Header components: VoltageDisplay, BatteryStatus, LoginIndicator
- Data polling with visibility awareness
- Bundle size: ~100KB gzipped

Also adds README.md and WIKI.md documentation

sample_interface/vitest.config.ts

@@ -0,0 +1,18 @@
+import { defineConfig } from 'vitest/config';
+import react from '@vitejs/plugin-react';
+import path from 'path';
+
+export default defineConfig({
+  plugins: [react()],
+  test: {
+    environment: 'jsdom',
+    setupFiles: ['./src/test/setup.ts'],
+    globals: true,
+    include: ['src/**/*.{test,spec}.{js,ts,jsx,tsx}'],
+  },
+  resolve: {
+    alias: {
+      '@': path.resolve(__dirname, './src'),
+    },
+  },
+});