Support HEAD requests on all public routes

Gin does not automatically handle HEAD for GET routes. Add a getAndHead
helper that registers both methods, and use it for all public-facing
routes (home, posts, tags, search, sitemap). Fixes curl -I and similar
tools returning 404 instead of 200.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: compscidr

goblog.go

@@ -397,8 +397,8 @@ func main() {
 		c.File(filepath.Join("themes", activeTheme, "static", fp))
 	})
 
-	router.GET("/", goblog.rootHandler)
-	router.GET("/login", goblog.loginHandler)
+	getAndHead(router, "/", goblog.rootHandler)
+	getAndHead(router, "/login", goblog.loginHandler)
 	router.GET("/wizard", goblog._wizard.SaveToken)
 	router.POST("/wizard_db", updateDB)
 	router.POST("/test_db", testDB)
@@ -463,16 +463,16 @@ func (g goblog) addRoutes() {
 	//the json API. The json API is tested more easily. Also javascript can
 	//served in the html can be used to create and update posts by directly
 	//working with the json API.
-	g.router.GET("/index.php", g._blog.Home)
-	g.router.GET("/posts/:yyyy/:mm/:dd/:slug", g._blog.Post)
+	getAndHead(g.router, "/index.php", g._blog.Home)
+	getAndHead(g.router, "/posts/:yyyy/:mm/:dd/:slug", g._blog.Post)
 	// lets posts work with our without the word posts in front
-	g.router.GET("/:yyyy/:mm/:dd/:slug", g._blog.Post)
+	getAndHead(g.router, "/:yyyy/:mm/:dd/:slug", g._blog.Post)
 	g.router.GET("/admin/posts/:yyyy/:mm/:dd/:slug", g._admin.Post)
-	g.router.GET("/tag/*name", g._blog.Tag)
+	getAndHead(g.router, "/tag/*name", g._blog.Tag)
 	g.router.GET("/logout", g._blog.Logout)
 
-	g.router.GET("/search", g._blog.Search)
-	g.router.GET("/sitemap.xml", g._blog.Sitemap)
+	getAndHead(g.router, "/search", g._blog.Search)
+	getAndHead(g.router, "/sitemap.xml", g._blog.Sitemap)
 	// lets old WordPress stuff stored at wp-content/uploads work
 	g.router.Use(static.Serve("/wp-content", static.LocalFile("www", false)))
 
@@ -489,6 +489,13 @@ func (g goblog) addRoutes() {
 	g.router.NoRoute(g._blog.NoRoute)
 }
 
+// getAndHead registers a handler for both GET and HEAD on the given path.
+// HEAD is required by the HTTP spec for any resource that supports GET.
+func getAndHead(router *gin.Engine, path string, handler gin.HandlerFunc) {
+	router.GET(path, handler)
+	router.HEAD(path, handler)
+}
+
 func CORS() gin.HandlerFunc {
 	return func(c *gin.Context) {
 		c.Writer.Header().Set("Access-Control-Allow-Origin", "*")