refactor(backups): standardize backup file naming using getBackupTimestamp utility

- Replaced inline timestamp generation with the new getBackupTimestamp function across various backup modules (compose, libsql, mariadb, mongo, mysql, postgres, web-server, and volume-backups).
- Improved code readability and maintainability by centralizing timestamp formatting logic.

packages/server/src/utils/backups/utils.ts

@@ -56,6 +56,9 @@ export const removeScheduleBackup = (backupId: string) => {
 	currentJob?.cancel();
 };
 
+export const getBackupTimestamp = () =>
+	new Date().toISOString().replace(/[:.]/g, "-");
+
 export const normalizeS3Path = (prefix: string) => {
 	// Trim whitespace and remove leading/trailing slashes
 	const normalizedPrefix = prefix.trim().replace(/^\/+|\/+$/g, "");