feat(aigc): implement travel AIGC feature and clean up legacy assets

- Replace all local static AIGC assets with OSS hosted URLs to reduce bundle size
- Add travelAIGC command to ChatModel and update quick access menu to link to AIGC home
- Implement AIGC user consent flow with local storage persistence for compliance
- Refactor Discovery page layout, remove unused HeritageDiscoverySection component
- Update ChatTopNavBar to support dynamic navigation bar height based on system info
- Restructure ChatMainList layout for better discovery panel interaction
- Remove deprecated local asset files and clean up unused imports across codebase

src/constant/aigc.js

@@ -0,0 +1,16 @@
+import { currentClientType } from "@/constant/base";
+
+const CLIENT_TYPE = currentClientType();
+const AIGC_CONSENT_AGREED = `${CLIENT_TYPE}_AIGC_CONSENT_AGREED`;
+
+export const getAigcConsentAgreed = () => {
+  return uni.getStorageSync(AIGC_CONSENT_AGREED);
+};
+
+export const setAigcConsentAgreed = (agreed = true) => {
+  return uni.setStorageSync(AIGC_CONSENT_AGREED, agreed);
+};
+
+export const removeAigcConsentAgreed = () => {
+  return uni.removeStorageSync(AIGC_CONSENT_AGREED);
+};