fix: default parse mode to text

internal/platform/telegram/telegram.go

@@ -237,13 +237,13 @@ func (t *TelegramPlatform) SendMessage(msg *model.Message) error {
 		"text":    msg.Text,
 	}
 
-	// Set parse_mode based on plugin preference or default to Markdown
+	// Set parse_mode based on plugin preference or default to empty string
 	if msg.Raw != nil && msg.Raw["parse_mode"] != nil {
 		// Plugin explicitly set parse_mode
 		payload["parse_mode"] = msg.Raw["parse_mode"]
 	} else {
-		// Default to Markdown for backward compatibility
-		payload["parse_mode"] = "Markdown"
+		// Default to empty string (no formatting)
+		payload["parse_mode"] = ""
 	}
 
 	// Add reply if needed