font Serve Vazirmatn WOFF2 with explicit Content-Type headers

Switch Vazirmatn font-face from TTF-only to WOFF2 to halve the
font payload (~50 KB vs ~105 KB per weight). Add a staticHandler
middleware that injects font/ttf and font/woff2 Content-Type headers
so browsers don't reject them as application/octet-stream.

internal/app/server.go

@@ -267,8 +267,26 @@ func (s *Server) ListenAndServe() error {
 
 func (s *Server) Close() error { return s.store.Close() }
 
+// staticHandler wraps a file server so font files always get the correct
+// Content-Type — Go's http.DetectContentType can return application/octet-stream
+// for .ttf files on older Go versions.
+func staticHandler(fs http.FileSystem) http.Handler {
+	h := http.FileServer(fs)
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		path := strings.TrimPrefix(r.URL.Path, "/static/")
+		switch {
+		case strings.HasSuffix(path, ".ttf"):
+			w.Header().Set("Content-Type", "font/ttf")
+		case strings.HasSuffix(path, ".woff"), strings.HasSuffix(path, ".woff2"):
+			w.Header().Set("Content-Type", "font/woff2")
+		}
+		h.ServeHTTP(w, r)
+	})
+}
+
 func (s *Server) routes(mux *http.ServeMux) {
-	mux.Handle("GET /static/", http.FileServer(http.FS(assets)))
+	fs := http.FS(assets)
+	mux.Handle("GET /static/", staticHandler(fs))
 	mux.Handle("GET /uploads/avatars/", http.StripPrefix("/uploads/avatars/", http.FileServer(http.Dir(filepath.Join(filepath.Dir(s.cfg.DatabasePath), "avatars")))))
 	mux.HandleFunc("GET /healthz", s.health)
 	mux.HandleFunc("GET /login", s.loginPage)