feat: add ntfy push notification for update checker

Update notifications now go through three channels:
- Admin dashboard banner (existing)
- Email to admin (added in previous commit)
- ntfy push notification (new)

Configure in app.ini:
  [ntfy]
  ENABLED = true
  SERVER_URL = https://ntfy.mokoconsulting.tech
  DEFAULT_TOPIC = mokogitea
  TOKEN = (optional bearer token)

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

services/mailer/mail_update.go

@@ -4,8 +4,11 @@
 package mailer
 
 import (
+	"bytes"
 	"context"
 	"fmt"
+	"io"
+	"net/http"
 
 	user_model "git.mokoconsulting.tech/MokoConsulting/MokoGitea/models/user"
 	"git.mokoconsulting.tech/MokoConsulting/MokoGitea/modules/log"
@@ -13,19 +16,8 @@ import (
 	sender_service "git.mokoconsulting.tech/MokoConsulting/MokoGitea/services/mailer/sender"
 )
 
-// SendUpdateNotification emails all admin users when a new MokoGitea version is available.
+// SendUpdateNotification emails the admin and sends ntfy push when a new MokoGitea version is available.
 func SendUpdateNotification(version, channel, releaseURL, dockerImage string) {
-	if setting.MailService == nil {
-		log.Debug("Update notification skipped: mail service not configured")
-		return
-	}
-
-	admin, err := user_model.GetAdminUser(context.Background())
-	if err != nil {
-		log.Error("SendUpdateNotification: GetAdminUser: %v", err)
-		return
-	}
-
 	subject := fmt.Sprintf("[MokoGitea] Update available: %s (%s)", version, channel)
 
 	body := fmt.Sprintf(`MokoGitea Update Available
@@ -45,9 +37,57 @@ Current:  %s`, channel, version, channel, setting.AppVer)
 
 	body += fmt.Sprintf("\n\nUpdate the channel in Site Administration > Dashboard.\n\n— %s", setting.AppName)
 
-	msg := sender_service.NewMessage(admin.EmailTo(), subject, body)
-	msg.Info = "Update notification"
+	// Send email to admin
+	if setting.MailService != nil {
+		admin, err := user_model.GetAdminUser(context.Background())
+		if err != nil {
+			log.Error("SendUpdateNotification: GetAdminUser: %v", err)
+		} else {
+			msg := sender_service.NewMessage(admin.EmailTo(), subject, body)
+			msg.Info = "Update notification"
+			SendAsync(msg)
+			log.Info("Update email sent to %s for version %s [%s]", admin.Email, version, channel)
+		}
+	}
 
-	SendAsync(msg)
-	log.Info("Update notification sent to %s for version %s [%s]", admin.Email, version, channel)
+	// Send ntfy push notification
+	if setting.Ntfy.Enabled && setting.Ntfy.ServerURL != "" {
+		sendNtfyNotification(subject, body, releaseURL)
+	}
+}
+
+func sendNtfyNotification(title, body, clickURL string) {
+	url := fmt.Sprintf("%s/%s", setting.Ntfy.ServerURL, setting.Ntfy.DefaultTopic)
+
+	req, err := http.NewRequest("POST", url, bytes.NewBufferString(body))
+	if err != nil {
+		log.Error("ntfy: create request: %v", err)
+		return
+	}
+
+	req.Header.Set("Title", title)
+	req.Header.Set("Priority", "high")
+	req.Header.Set("Tags", "arrow_up,mokogitea")
+	if clickURL != "" {
+		req.Header.Set("Click", clickURL)
+	}
+	if setting.Ntfy.Token != "" {
+		req.Header.Set("Authorization", "Bearer "+setting.Ntfy.Token)
+	}
+
+	client := &http.Client{}
+	resp, err := client.Do(req)
+	if err != nil {
+		log.Error("ntfy: send notification: %v", err)
+		return
+	}
+	defer resp.Body.Close()
+	io.Copy(io.Discard, resp.Body)
+
+	if resp.StatusCode >= 300 {
+		log.Error("ntfy: unexpected status %d", resp.StatusCode)
+		return
+	}
+
+	log.Info("ntfy: update notification sent to %s/%s", setting.Ntfy.ServerURL, setting.Ntfy.DefaultTopic)
 }