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/.bundlesize.json

@@ -0,0 +1,10 @@
+{
+  "files": [
+    {
+      "path": "dist/assets/*.js",
+      "maxSize": "200kB",
+      "compression": "gzip"
+    }
+  ],
+  "strict": false
+}