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/useTemplate/components/VersionOptionList/index.vue

@@ -2,9 +2,9 @@
   <view class="version-option-list">
     <VersionOptionCard
       v-for="option in options"
-      :key="option.value"
+      :key="option.templateItemId"
       :option="option"
-      :selected="option.value === selectedValue"
+      :selected="option.templateItemId === selectedValue"
       @select="emit('select', $event)"
     />
   </view>