feat: implement tag management and search functionality

Features:
- Tag system with multi-language support (Chinese/English)
- Auto-create tags when associating with articles
- Tag filtering on homepage with visual indicators
- Full-text search across title, summary, and content
- Tag cloud sidebar showing article counts
- Search page with results display

Technical Implementation:
- Database models: Tag, ArticleTag (many-to-many)
- Tag count caching for performance
- Automatic tag slug generation
- Responsive design with mobile support
- I18n support for all new UI elements

Bug Fix:
- Fixed SQL column ambiguity error in tag filtering
- Added table prefix to ORDER BY clause in publishedArticleOrder

Routes:
- GET /search - Search results page
- GET /?tag=<slug> - Filter articles by tag
- GET /api/articles?tag=<slug> - API with tag filter support

Templates:
- Added tag input field to article create/edit form
- Added search box to homepage header
- Added tag cloud sidebar on homepage and search page
- Created new search results page template

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

main.go

@@ -50,11 +50,14 @@ func main() {
 
 	// 8. Register routes.
 	router.GET("/", handlers.HomePage(db))
+	router.GET("/search", handlers.SearchPage(db))
 	router.GET("/api/articles", handlers.HomeArticlesAPI(db))
 	router.GET("/rss", handlers.RSSFeed(db))
 	router.GET("/feed", handlers.RSSFeed(db))
 	router.GET("/login", handlers.LoginPage())
 	router.POST("/login", handlers.Login(db))
+	router.GET("/register", handlers.RegisterPage(db))
+	router.POST("/register", handlers.Register(db))
 	router.POST("/logout", handlers.Logout())
 	router.GET("/article/:slug", handlers.ArticleDetail(db))
 	router.POST("/article/:slug/comments", handlers.PostComment(db))
@@ -110,6 +113,8 @@ func main() {
 	{
 		settings.GET("/site", handlers.SiteSettingsPage(db))
 		settings.POST("/site", handlers.SiteSettingsSave(db, cfg.Path))
+		settings.GET("/navlinks", handlers.NavLinksSettingsPage(db))
+		settings.POST("/navlinks", handlers.NavLinksSettingsSave(db))
 		settings.GET("/upload", handlers.UploadSettingsPage(db))
 		settings.POST("/upload", handlers.UploadSettingsSave(db))
 		settings.GET("/download", handlers.DownloadSettingsPage(db))