feat: add heritage discovery tab and AIGC consent dialog

- Add new HeritageDiscoverySection and HeritageQuickPrompts components for dedicated heritage discovery view
- Implement reusable AigcConsentDialog component for AI service user agreement prompts
- Update Discovery page to toggle between explore and heritage tab layouts
- Refactor legacy CardSwiper component into generic ExploreCards
- Adjust ChatMainList layout to include home hero sprite animation and restructure welcome section
- Refine NoticeMessage component styling and layout for better consistency
- Add build best practices guidance to AGENTS.md documentation
- Clean up minor config whitespace and formatting issues across files

src/pages/ChatMain/ChatMainList/styles/index.scss

@@ -3,4 +3,26 @@
   height: 0;
   min-height: 0;
   overscroll-behavior-y: contain;
-}
+}
+
+.home-hero {
+  height: 136px;
+  overflow: hidden;
+}
+
+.home-hero-bg {
+  height: 136px;
+}
+
+.home-hero-sprite {
+  position: absolute;
+  left: 50%;
+  bottom: 0;
+  z-index: 4;
+  transform: translateX(-50%);
+  pointer-events: none;
+}
+
+.home-tabs-layer {
+  z-index: 3;
+}