feat: refactor monolithic App.vue into modular Vue component architecture

- Extract 711-line App.vue into 15+ focused files across 5 directories
- Add data layer (icons, metrics, policies, auditTrail, requests)
- Add composables (useNavigation, useRequests, useChat, useToast)
- Add layout components (SidebarRail, TopBar, FilterBar)
- Add shared components (PanelHead, InfoRow, ToastNotification)
- Add business component (RequestTable) and 5 view components
- Extract global CSS to assets/styles/global.css
- Add start.sh with WSL/Windows cross-platform support
- Add .gitignore for node_modules, dist, and IDE dirs

src/views/PoliciesView.vue

@@ -0,0 +1,31 @@
+<template>
+  <section class="view single">
+    <article class="panel">
+      <PanelHead eyebrow="Policy automation" title="规则运行状态" note="把关键政策、阈值和命中表现集中维护。" />
+      <div class="list">
+        <InfoRow
+          v-for="policy in policies"
+          :key="policy.code"
+          :rank="policy.code"
+          :title="policy.title"
+          :note="policy.note"
+          :badge="policy.badge"
+          :tone="policy.tone"
+        />
+      </div>
+    </article>
+  </section>
+</template>
+
+<script setup>
+import PanelHead from '../components/shared/PanelHead.vue'
+import InfoRow from '../components/shared/InfoRow.vue'
+import { policies } from '../data/policies.js'
+</script>
+
+<style scoped>
+.view { display: grid; gap: 22px; animation: fadeUp 220ms var(--ease) both; }
+.view.single { max-width: 1120px; }
+.panel { padding: 20px; }
+.list { display: grid; gap: 12px; }
+</style>