feat: initial scaffold — Vite + React + Tailwind + MapLibre

Minimal Idaho basemap via local PMTiles extract from Protomaps
daily build (20260419). Deployed to /mnt/nav/frontend/ via rsync,
served by nginx on :8440 as navi.echo6.co.

Phase 3 Step 1 of Navi frontend.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

package.json

@@ -0,0 +1,34 @@
+{
+  "name": "navi",
+  "private": true,
+  "version": "0.0.0",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "vite build",
+    "lint": "eslint .",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "maplibre-gl": "^5.23.0",
+    "pmtiles": "^4.4.1",
+    "protomaps-themes-base": "^4.5.0",
+    "react": "^19.2.5",
+    "react-dom": "^19.2.5"
+  },
+  "devDependencies": {
+    "@eslint/js": "^9.39.4",
+    "@tailwindcss/postcss": "^4.2.2",
+    "@types/react": "^19.2.14",
+    "@types/react-dom": "^19.2.3",
+    "@vitejs/plugin-react": "^6.0.1",
+    "autoprefixer": "^10.5.0",
+    "eslint": "^9.39.4",
+    "eslint-plugin-react-hooks": "^7.1.1",
+    "eslint-plugin-react-refresh": "^0.5.2",
+    "globals": "^17.5.0",
+    "postcss": "^8.5.10",
+    "tailwindcss": "^4.2.2",
+    "vite": "^8.0.9"
+  }
+}