fix: address Discord webhook issues from #378

- Remove invalid url field from Discord embed (was causing 400 error)
- Remove SVG avatar/footer icons (Discord doesn't support SVG)
- Fix test webhook to use proper instance URL instead of 'pulse-monitoring'
- Discord webhook template now sends valid payloads

internal/notifications/notifications.go

@@ -1125,7 +1125,7 @@ func (n *NotificationManager) SendTestWebhook(webhook WebhookConfig) error {
 		ResourceID:   "webhook-test",
 		ResourceName: "Test Alert",
 		Node:         "test-node",
-		Instance:     "pulse-monitoring",
+		Instance:     "http://your-pulse-instance:7655", // Placeholder URL for test webhooks
 		Message:      fmt.Sprintf("This is a test alert from Pulse to verify your %s webhook is working correctly", webhook.Name),
 		Value:        85.5,
 		Threshold:    80.0,

internal/notifications/webhook_templates.go

@@ -22,11 +22,9 @@ func GetWebhookTemplates() []WebhookTemplate {
 			Headers:    map[string]string{"Content-Type": "application/json"},
 			PayloadTemplate: `{
 				"username": "Pulse Monitoring",
-				"avatar_url": "https://raw.githubusercontent.com/rcourtman/Pulse/main/frontend-modern/public/logo.svg",
 				"embeds": [{
 					"title": "Pulse Alert: {{.Level | title}}",
 					"description": "{{.Message}}",
-					"url": "{{.Instance}}",
 					"color": {{if eq .Level "critical"}}15158332{{else if eq .Level "warning"}}15105570{{else}}3447003{{end}},
 					"fields": [
 						{"name": "Resource", "value": "{{.ResourceName}}", "inline": true},
@@ -38,8 +36,7 @@ func GetWebhookTemplates() []WebhookTemplate {
 					],
 					"timestamp": "{{.Timestamp}}",
 					"footer": {
-						"text": "Pulse Monitoring",
-						"icon_url": "https://raw.githubusercontent.com/rcourtman/Pulse/main/frontend-modern/public/logo.svg"
+						"text": "Pulse Monitoring"
 					}
 				}]
 			}`,