feat(profile): Passkey-Labels, Sicherheits-Checkliste und Geräte-Block

Erweitert die Profilseite um benennbare Passkeys, Sicherheitsübersicht,
Gerät/Sync-Status, Backup-Hinweis in der Gefahrenzone und Dialog beim
Löschen des letzten Passkeys.

Co-authored-by: Cursor <cursoragent@cursor.com>

client/src/i18n/locales/en.json

@@ -295,7 +295,8 @@
       "add_passkey_success": "Passkey added successfully.",
       "add_passkey_failed": "Could not add passkey.",
       "remove_passkey_btn": "Remove passkey",
-      "remove_passkey_last": "The last passkey cannot be removed.",
+      "remove_passkey_last_title": "Last passkey",
+      "remove_passkey_last_desc": "The only passkey cannot be removed without losing access to your account. To delete the account entirely, use the danger zone at the bottom of this page.",
       "remove_passkey_failed": "Could not remove passkey.",
       "remove_passkey_confirm_title": "Remove passkey?",
       "remove_passkey_confirm_desc": "This device will no longer be able to sign in with this passkey.",
@@ -319,6 +320,31 @@
       "remove_pin_confirm_desc": "You will need to sign in on this device with passkey or recovery phrase again.",
       "remove_pin_confirm_yes": "Remove PIN",
       "remove_pin_confirm_no": "Cancel",
+      "security_title": "Security checklist",
+      "security_desc": "Overview of the most important protections for your account.",
+      "security_passkeys_ok": "At least one passkey registered",
+      "security_passkeys_missing": "No passkey registered",
+      "security_prf_ok": "PRF key derivation active",
+      "security_prf_missing": "PRF not configured",
+      "security_pin_ok": "Local PIN on this device",
+      "security_pin_missing": "No local PIN",
+      "security_recovery_ok": "Recovery phrase configured",
+      "security_recovery_hint": "The 12 words were shown at registration. Store them offline and separately from this device — they cannot be shown again.",
+      "device_title": "This device",
+      "device_desc": "Local cache, sync status, and quick login on this browser.",
+      "device_sync_pending": "{{count}} pending sync items",
+      "device_sync_ok": "All local changes synced",
+      "device_remembered": "Account saved for quick login on this device",
+      "device_not_remembered": "Account not in the quick-login list",
+      "device_forget_btn": "Forget account on this device",
+      "device_forget_confirm_title": "Remove quick login?",
+      "device_forget_confirm_desc": "The account will be removed from the quick-login list on this device. Your session and local logbooks stay on this device.",
+      "device_forget_confirm_yes": "Remove",
+      "passkey_label": "Name for new passkey (optional)",
+      "passkey_label_placeholder": "e.g. MacBook, iPhone",
+      "passkey_rename_btn": "Save name",
+      "passkey_rename_success": "Passkey name saved.",
+      "passkey_unnamed": "Unnamed passkey",
       "stats_title": "Statistics",
       "stats_subtitle": "Across all your logbooks on this device",
       "stats_logbooks": "Logbooks",
@@ -398,6 +424,7 @@
       "delete_account_confirm_yes": "Yes, Delete Account and All Data",
       "delete_account_confirm_no": "Cancel",
       "delete_account_failed": "Failed to delete account. Please try again.",
+      "delete_backup_hint": "Tip: Before deleting, create backups of your logbooks (.daagbok.json) in each logbook's settings.",
       "deleting_account": "Deleting account…",
       "tour_title": "App tour",
       "tour_desc": "Take a guided walkthrough of the main areas of the app again.",