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/recharge/components/RechargeFooter/styles/index.scss

@@ -42,3 +42,7 @@
   font-weight: 900;
   white-space: nowrap;
 }
+
+.recharge-pay-button.is-disabled {
+  opacity: 0.48;
+}