feat(aigc): add travel postcard AIGC feature

Add complete travel postcard AIGC creation workflow including:
- New AIGC pages: template selection home, result detail, and history records
- Reusable UI components: template card, flow steps, result preview, action buttons, record lists
- Static assets including template images, fonts and styles
- Updated TopNavBar component to support menu button alignment
- Register new AIGC page routes in pages.json
- Add mock data for templates, user records and result details

src/pages-aigc/home/components/FlowSteps/index.vue

@@ -0,0 +1,25 @@
+<template>
+  <view class="flow-steps">
+    <view
+      v-for="(step, index) in steps"
+      :key="step"
+      class="flow-step"
+    >
+      <text class="flow-index">{{ index + 1 }}</text>
+      <text class="flow-label">{{ step }}</text>
+    </view>
+  </view>
+</template>
+
+<script setup>
+defineProps({
+  steps: {
+    type: Array,
+    default: () => [],
+  },
+});
+</script>
+
+<style scoped lang="scss">
+@import "./styles/index.scss";
+</style>

src/pages-aigc/home/components/FlowSteps/styles/index.scss

@@ -0,0 +1,50 @@
+.flow-steps {
+  height: 55px;
+  display: grid;
+  grid-template-columns: repeat(4, 1fr);
+  gap: 0;
+  align-items: center;
+  margin: 12px 16px 0;
+  padding: 4px;
+  border-radius: 18px;
+  background: rgba(255, 255, 255, 0.62);
+  box-shadow: 0 8px 18px rgba(18, 48, 56, 0.05);
+  box-sizing: border-box;
+}
+
+.flow-step {
+  min-width: 0;
+  height: 38px;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  gap: 5px;
+  padding: 0 4px;
+  border-radius: 14px;
+  background: transparent;
+  color: #576276;
+  font-size: 12px;
+  line-height: 14px;
+  font-weight: 900;
+  white-space: nowrap;
+  box-sizing: border-box;
+}
+
+.flow-index {
+  flex: 0 0 18px;
+  width: 18px;
+  height: 18px;
+  border-radius: 50%;
+  background: #20cf75;
+  color: #ffffff;
+  font-size: 12px;
+  line-height: 18px;
+  text-align: center;
+}
+
+.flow-label {
+  min-width: 0;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}