add logo to toolbar

add test for logo handler

lint: unused param

app/webapi/assets/components/navbar.html

@@ -1,7 +1,9 @@
 <!-- Navbar -->
 <nav class="navbar navbar-expand-lg navbar-dark bg-dark">
     <div class="container-fluid">
-        <a class="navbar-brand" href="/">TG-Spam</a>
+        <a class="navbar-brand" href="/">
+            <img src="/logo.png" alt="Logo" style="height: 30px;"> TG-Spam
+        </a>
         <div class="collapse navbar-collapse">
             <ul class="navbar-nav me-auto mb-2 mb-lg-0">
                 <li class="nav-item">

app/webapi/webapi.go

@@ -163,6 +163,8 @@ func (s *Server) routes(router *chi.Mux) *chi.Mux {
 		webUI.Get("/manage_samples", s.htmlManageSamplesHandler) // serve manage samples page
 		webUI.Get("/manage_users", s.htmlManageUsersHandler)     // serve manage users page
 		webUI.Get("/styles.css", s.stylesHandler)                // serve styles.css
+		webUI.Get("/logo.png", s.logoHandler)                    // serve logo.png
+
 	})
 
 	return router
@@ -486,6 +488,18 @@ func (s *Server) stylesHandler(w http.ResponseWriter, _ *http.Request) {
 	_, _ = w.Write(body)
 }
 
+// logoHandler handles GET /logo.png request. It returns assets/logo.png file.
+func (s *Server) logoHandler(w http.ResponseWriter, _ *http.Request) {
+	img, err := templateFS.ReadFile("assets/logo.png")
+	if err != nil {
+		http.Error(w, "Logo not found", http.StatusNotFound)
+		return
+	}
+	w.Header().Set("Content-Type", "image/png")
+	w.WriteHeader(http.StatusOK)
+	_, _ = w.Write(img)
+}
+
 func (s *Server) renderSamples(w http.ResponseWriter) {
 	spam, ham, err := s.SpamFilter.DynamicSamples()
 	if err != nil {

app/webapi/webapi_test.go

@@ -837,6 +837,19 @@ func TestServer_stylesHandler(t *testing.T) {
 	assert.Contains(t, rr.Body.String(), "body", "handler should return CSS content")
 }
 
+func TestServer_logoHandler(t *testing.T) {
+	server := NewServer(Config{Version: "1.0"})
+	rr := httptest.NewRecorder()
+	req, err := http.NewRequest("GET", "/logo.png", http.NoBody)
+	require.NoError(t, err)
+
+	handler := http.HandlerFunc(server.logoHandler)
+	handler.ServeHTTP(rr, req)
+
+	assert.Equal(t, http.StatusOK, rr.Code, "handler should return status OK")
+	assert.Equal(t, "image/png", rr.Header().Get("Content-Type"), "handler should return CSS content type")
+}
+
 func TestServer_getDynamicSamplesHandler(t *testing.T) {
 	mockSpamFilter := &mocks.SpamFilterMock{
 		DynamicSamplesFunc: func() ([]string, []string, error) {