feat: SMTP test button in admin modal — sends real test email, shows result

cmd/verstak-server/server.go

@@ -332,6 +332,7 @@ func (s *Server) routes() *http.ServeMux {
 	mux.HandleFunc("/admin/login", s.handleAdminLogin)
 	mux.HandleFunc("/admin/dashboard", s.handleAdminDashboard)
 	mux.HandleFunc("/admin/api/stats", s.handleAdminStats)
+	mux.HandleFunc("/admin/api/smtp/test", s.handleAdminSMTPTest)
 	mux.HandleFunc("/admin/", s.handleAdminAPI)
 	mux.HandleFunc("/", s.handleNotFound)
 	return mux
@@ -475,6 +476,46 @@ func (s *Server) smtpSend(to, subject, body string) error {
 	return err
 }
 
+func (s *Server) smtpTest(host, port, user, pass, from, to string) error {
+	if host == "" || port == "" || from == "" {
+		return fmt.Errorf("SMTP not configured")
+	}
+	addr := net.JoinHostPort(host, port)
+	msg := []byte("From: " + from + "\r\nTo: " + to + "\r\nSubject: Test from Verstak Sync\r\n\r\nThis is a test email from Verstak Sync Server.\r\n")
+	if user != "" {
+		auth := smtp.PlainAuth("", user, pass, host)
+		if port == "465" {
+			tlsCfg := &tls.Config{ServerName: host}
+			conn, err := tls.Dial("tcp", addr, tlsCfg)
+			if err != nil {
+				return err
+			}
+			cl, err := smtp.NewClient(conn, host)
+			if err != nil {
+				return err
+			}
+			defer cl.Close()
+			if err := cl.Auth(auth); err != nil {
+				return err
+			}
+			if err := cl.Mail(from); err != nil {
+				return err
+			}
+			if err := cl.Rcpt(to); err != nil {
+				return err
+			}
+			w, err := cl.Data()
+			if err != nil {
+				return err
+			}
+			w.Write(msg)
+			return w.Close()
+		}
+		return smtp.SendMail(addr, auth, from, []string{to}, msg)
+	}
+	return smtp.SendMail(addr, nil, from, []string{to}, msg)
+}
+
 // ============================================================
 // User helpers
 // ============================================================
@@ -1438,10 +1479,20 @@ function copyKey(key,btn){
   })
 }
 function delKey(id){if(confirm('Удалить ключ?'))fetch('/admin/api/keys/'+id,{method:'DELETE'}).then(()=>location.reload())}
-function openSMTP(){document.getElementById('smtp-modal').style.display='flex'}
+function openSMTP(){document.getElementById('smtp-modal').style.display='flex';document.getElementById('smtp-test-result').textContent=''}
 function closeSMTP(e){if(!e||e.target.id==='smtp-modal')document.getElementById('smtp-modal').style.display='none'}
 function openHealth(){var m=document.getElementById('health-modal');m.style.display='flex';document.getElementById('health-result').textContent='Загрузка...';fetch('/api/v1/health').then(function(r){return r.text()}).then(function(t){document.getElementById('health-result').textContent=t})}
 function closeHealth(e){if(!e||e.target.id==='health-modal')document.getElementById('health-modal').style.display='none'}
+function testSMTP(){
+  var f=document.querySelector('#smtp-modal form')
+  var fd=new FormData(f)
+  var r=document.getElementById('smtp-test-result')
+  r.textContent='⏳ Тестируем...';r.style.color='#888'
+  fetch('/admin/api/smtp/test',{method:'POST',body:fd}).then(function(r2){return r2.json()}).then(function(d){
+    r.textContent=d.ok?'✓ Тест пройден':'✗ '+d.error
+    r.style.color=d.ok?'#4ade80':'#ff6b6b'
+  }).catch(function(e){r.textContent='✗ '+e;r.style.color='#ff6b6b'})
+}
 </script>
 
 <h3>Новый ключ</h3>
@@ -1461,7 +1512,11 @@ function closeHealth(e){if(!e||e.target.id==='health-modal')document.getElementB
 <div class="form-row"><label>Пароль</label><input type="password" name="smtp_pass" placeholder="••••••••"></div>
 <div class="form-row"><label>От кого</label><input name="smtp_from" value="` + smtpFrom + `" placeholder="noreply@example.com"></div>
 <div class="form-row"><label>URL сервера</label><input name="server_url" value="` + srvURL + `" placeholder="https://example.com:47732"></div>
-<div style="margin-top:12px"><button class="btn btn-primary">Сохранить SMTP</button></div>
+<div style="margin-top:12px;display:flex;gap:8px;align-items:center">
+<button class="btn btn-primary">Сохранить SMTP</button>
+<button class="btn" type="button" onclick="testSMTP()">Test</button>
+<span id="smtp-test-result" style="font-size:12px"></span>
+</div>
 </form>
 </div>
 </div>
@@ -1487,6 +1542,34 @@ func (s *Server) handleAdminStats(w http.ResponseWriter, r *http.Request) {
 	jsonOK(w, map[string]int{"ops": opsCount})
 }
 
+func (s *Server) handleAdminSMTPTest(w http.ResponseWriter, r *http.Request) {
+	if !s.requireAdmin(w, r) {
+		return
+	}
+	if err := r.ParseForm(); err != nil {
+		jsonErr(w, 400, "bad form")
+		return
+	}
+	host := r.FormValue("smtp_host")
+	port := r.FormValue("smtp_port")
+	user := r.FormValue("smtp_user")
+	pass := r.FormValue("smtp_pass")
+	from := r.FormValue("smtp_from")
+	to := r.FormValue("test_to")
+	if to == "" {
+		to = from
+	}
+	if host == "" || port == "" || from == "" {
+		jsonOK(w, map[string]interface{}{"ok": false, "error": "host, port and from required"})
+		return
+	}
+	if err := s.smtpTest(host, port, user, pass, from, to); err != nil {
+		jsonOK(w, map[string]interface{}{"ok": false, "error": err.Error()})
+		return
+	}
+	jsonOK(w, map[string]interface{}{"ok": true})
+}
+
 func (s *Server) handleAdminAPI(w http.ResponseWriter, r *http.Request) {
 	if !s.requireAdmin(w, r) {
 		return