feat: version 0.9.30 - cache invalidation fixes

🔧 Fixed cache invalidation for featured materials:
- Enhanced invalidate_shout_related_cache with featured keys
- Fixed set_featured/set_unfeatured functions with async cache invalidation
- Materials now correctly appear/disappear from main page on feature/unfeature

✅ Code Quality: Python Standards Compliance
- Ruff linting & formatting checks passed
- MyPy type checking passed
- All functions have proper type hints and docstrings
- Tests passing successfully

Version bump: 0.9.30

package.json

@@ -1,6 +1,6 @@
 {
   "name": "publy-panel",
-  "version": "0.9.28",
+  "version": "0.9.30",
   "type": "module",
   "description": "Publy, a modern platform for collaborative text creation, offers a user-friendly interface for authors, editors, and readers, supporting real-time collaboration and structured feedback.",
   "scripts": {