feat(settings): add database backup management

public/locales/en.json

@@ -752,7 +752,23 @@
     "memberContactBirthdayHint": "This member is automatically synchronized with Contacts and Birthdays.",
     "memberBirthDateInvalid": "Use a valid birthday date in the selected date format.",
     "memberPhoneMeta": "Phone: {{value}}",
-    "memberBirthdayMeta": "Birthday: {{date}}"
+    "memberBirthdayMeta": "Birthday: {{date}}",
+    "tabBackup": "Backup Management",
+    "sectionBackup": "Backup Management",
+    "backupDownloadTitle": "Download database backup",
+    "backupDownloadHint": "Create a consistent SQLite backup of all application data.",
+    "backupDownloadButton": "Download backup",
+    "backupRestoreTitle": "Restore database backup",
+    "backupRestoreHint": "Restore replaces the current database. Download a fresh backup before continuing.",
+    "backupDropzoneTitle": "Drop a backup file here or click to select",
+    "backupDropzoneHint": "SQLite backup files: .db, .sqlite or .sqlite3",
+    "backupRestoreButton": "Restore backup",
+    "backupRestoreConfirm": "Restoring this backup will replace the current database for everyone. Continue?",
+    "backupRestoring": "Restoring...",
+    "backupRestoredToast": "Database restored. Reloading...",
+    "backupCliTitle": "CLI / Docker Compose restore",
+    "backupCliHint": "For operational restores, copy the backup into the container and run the restore helper.",
+    "backupCliBackupHint": "You can also create a backup directly from Docker Compose:"
   },
   "login": {
     "tagline": "Family planning. Secure. Privacy-friendly. Open source.",