feat(router): migrate to declarative view-based navigation system

- Introduce unified View hierarchy (VIEW_TREE) with parent/child relationships
- Add useViewRouter for navigate(), goBack(), openArticle(), and dynamic child navigation
- Replace legacy boolean-based view flags with single ui.view state
- Implement dynamic component rendering via VIEW_COMPONENTS map
- Add HomeView wrapper and integrate dynamic navigation props
- Update ArticleView to use open_editor and new ArticleViewProps
- Adjust ArticleEditor props type to accept null article
- Normalize navigation prop naming (open_* passed as onBack/onEdit via router)
- Enforce validation: prevent article updates without logged-in user
- Remove old conditional rendering/switch blocks and simplify Blog.tsx
- Version bump: 0.2.3 → 0.2.4

package.json

@@ -1,6 +1,6 @@
 {
   "name": "aetoskia-blog-app",
-  "version": "0.2.3",
+  "version": "0.2.4",
   "private": true,
   "scripts": {
     "dev": "vite",