feat(aigc): fully integrate backend API and replace mock data

- Replace all static mock data with real backend API calls for templates, generation tasks, credit balance and recharge
- Remove deprecated mock data files including templates.js, versionOptions.js, records.js and packages.js
- Add useCurrentCredit composable for fetching and managing user credit balance
- Update all components to align with new backend data shapes (e.g. templateItemId instead of id)
- Add loading and disabled states for interactive UI elements
- Implement full WeChat mini-program payment flow for credit recharge
- Fix template and record card UI styling and media handling
- Set developVersion flag to true for testing environment

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

@@ -22,7 +22,7 @@
       <view class="template-track">
         <TemplateCard
           v-for="(template, index) in templates"
-          :key="template.id || index"
+          :key="template.templateId || index"
           :template="template"
           :active="index === modelValue"
           @select="handleSelect(template, index)"
@@ -33,7 +33,7 @@
     <view class="template-dots">
       <view
         v-for="(template, index) in templates"
-        :key="`${template.id || index}-dot`"
+        :key="`${template.templateId || index}-dot`"
         class="template-dot"
         :class="{ 'is-active': index === modelValue }"
       />