feat: project scaffold + bridge + maplibre engine

- Vite + Vue 3 + TypeScript strict
- @yuto-water/js-bridge (types, detector, browser provider)
- MapLibre engine (MapManager singleton, MapFactory, LayerFactory)
- Map composables (useMap, useLayer, usePopup)
- Tianditu tile source, 6 layer type factory
- SCSS design tokens (water-blue theme, dark mode)
- Vant 4, maplibre-gl, axios, pinia, echarts deps
- Build passes (vue-tsc + vite)

src/components/HelloWorld.vue

@@ -0,0 +1,18 @@
+<script setup lang="ts">
+// Minimal placeholder component
+</script>
+
+<template>
+  <div class="hello-world">
+    <h1>智慧水务</h1>
+  </div>
+</template>
+
+<style scoped>
+.hello-world {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  min-height: 200px;
+}
+</style>