feat(settings): sweep a private key's funds to your own wallet

Add a "Sweep to my wallet (don't keep the key)" option to the Import Private
Key dialog (spending keys only). Rather than keeping the key, it imports the
key, then sends ALL its funds to a destination you control — a freshly
generated shielded address by default, or an existing wallet address you pick.

Flow (App::sweepPrivateKey): import the key (rescan; the stock node has no
address index, so its UTXOs/notes can't be enumerated otherwise) → confirm it
holds spendable funds → resolve the destination → z_sendmany balance-minus-fee
from the key's address to the destination, via the existing tested submitZSendMany
wrapper + async-operation tracker. The imported key is left in the wallet with an
empty balance (there is no remove-key RPC) — stated plainly in the UI caveat.

Design notes forced by this daemon (verified against external/dragonx):
- z_importkey returns null here, so the shielded source address is found by
  diffing z_listaddresses before/after import (aborts if the pre-snapshot fails,
  so a wrong address can never be picked). Transparent uses importprivkey's return.
- z_sendmany, NOT z_mergetoaddress: moves a single-UTXO transparent source (the
  common paper-wallet case) and fails loudly instead of silently leaving a
  remainder. Amount computed in integer satoshis for an exact fixed-decimal string.
- Clear errors for no-funds / unconfirmed / dust-below-fee / already-imported.
- The mode + destination are locked during a running sweep; a sweep that finishes
  while the dialog is closed still shows its Done/Error+txid on reopen; sweep UI
  can't bleed into the watch-only viewing dialog.

i18n: 8 new sweep_* keys (en + 8 langs); dynamic status strings are English,
matching the beginSweepToSeedWallet precedent.

Reviewed across three adversarial multi-agent rounds (fund-safety focus): round 1
caught the feature was broken for shielded keys (z_importkey null) and rejected
single-UTXO transparent sources; round 2 caught reopen/double-submit/precision
issues; round 3 verified the fixes. NOT yet exercised against a live daemon —
needs a small-amount mainnet test before it's trusted, like migrate-to-seed.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

res/lang/de.json

@@ -1202,6 +1202,14 @@
     "submitting_transaction": "Transaktion wird übermittelt...",
     "success": "Erfolg",
     "summary": "Zusammenfassung",
+    "sweep_button": "Fegen",
+    "sweep_caveat": "Importiert den Schlüssel, um eine Transaktion zu signieren, die alle Mittel an Ihre Adresse verschiebt. Der Schlüssel bleibt mit leerem Guthaben in Ihrer Wallet.",
+    "sweep_dest_label": "Gefegte Mittel senden an",
+    "sweep_dest_new": "Neue abgeschirmte Adresse (empfohlen)",
+    "sweep_done": "Fertig — Mittel an Ihre Adresse gefegt.",
+    "sweep_to": "Gefegt an:",
+    "sweep_toggle": "In meine Wallet fegen (Schlüssel nicht behalten)",
+    "sweep_tx": "Transaktion:",
     "syncing": "Synchronisiere...",
     "t_address": "T-Adresse",
     "t_addresses": "T-Adressen",

res/lang/es.json

@@ -1202,6 +1202,14 @@
     "submitting_transaction": "Enviando transacción...",
     "success": "Éxito",
     "summary": "Resumen",
+    "sweep_button": "Barrer",
+    "sweep_caveat": "Importa la clave para firmar una transacción que mueve todos sus fondos a tu dirección. La clave permanece en tu monedero con saldo cero.",
+    "sweep_dest_label": "Enviar los fondos barridos a",
+    "sweep_dest_new": "Nueva dirección blindada (recomendado)",
+    "sweep_done": "Listo — fondos barridos a tu dirección.",
+    "sweep_to": "Barrido a:",
+    "sweep_toggle": "Barrer a mi monedero (no conservar la clave)",
+    "sweep_tx": "Transacción:",
     "syncing": "Sincronizando...",
     "t_address": "Dirección T",
     "t_addresses": "Direcciones T",

res/lang/fr.json

@@ -1202,6 +1202,14 @@
     "submitting_transaction": "Soumission de la transaction...",
     "success": "Succès",
     "summary": "Résumé",
+    "sweep_button": "Balayer",
+    "sweep_caveat": "Importe la clé pour signer une transaction qui déplace tous ses fonds vers votre adresse. La clé reste dans votre portefeuille avec un solde vide.",
+    "sweep_dest_label": "Envoyer les fonds balayés vers",
+    "sweep_dest_new": "Nouvelle adresse blindée (recommandé)",
+    "sweep_done": "Terminé — fonds balayés vers votre adresse.",
+    "sweep_to": "Balayé vers :",
+    "sweep_toggle": "Balayer vers mon portefeuille (ne pas conserver la clé)",
+    "sweep_tx": "Transaction :",
     "syncing": "Synchronisation...",
     "t_address": "Adresse T",
     "t_addresses": "Adresses T",

res/lang/ja.json

@@ -1202,6 +1202,14 @@
     "submitting_transaction": "取引を送信中...",
     "success": "成功",
     "summary": "概要",
+    "sweep_button": "集約",
+    "sweep_caveat": "鍵をインポートして、すべての資金をあなたのアドレスへ移す取引に署名します。鍵は残高ゼロでウォレットに残ります。",
+    "sweep_dest_label": "集約先",
+    "sweep_dest_new": "新しいシールドアドレス（推奨）",
+    "sweep_done": "完了 — 資金をあなたのアドレスに集約しました。",
+    "sweep_to": "集約先:",
+    "sweep_toggle": "ウォレットに集約（鍵は保持しない）",
+    "sweep_tx": "取引:",
     "syncing": "同期中...",
     "t_address": "Tアドレス",
     "t_addresses": "Tアドレス",

res/lang/ko.json

@@ -1202,6 +1202,14 @@
     "submitting_transaction": "거래 제출 중...",
     "success": "성공",
     "summary": "요약",
+    "sweep_button": "쓸어담기",
+    "sweep_caveat": "키를 가져와 모든 자금을 내 주소로 옮기는 거래에 서명합니다. 키는 잔액이 0인 상태로 지갑에 남습니다.",
+    "sweep_dest_label": "쓸어담은 자금을 보낼 주소",
+    "sweep_dest_new": "새 차폐 주소 (권장)",
+    "sweep_done": "완료 — 자금을 내 주소로 쓸어담았습니다.",
+    "sweep_to": "쓸어담은 주소:",
+    "sweep_toggle": "내 지갑으로 쓸어담기 (키 보관 안 함)",
+    "sweep_tx": "거래:",
     "syncing": "동기화 중...",
     "t_address": "T 주소",
     "t_addresses": "T 주소",

res/lang/pt.json

@@ -1202,6 +1202,14 @@
     "submitting_transaction": "Enviando transação...",
     "success": "Sucesso",
     "summary": "Resumo",
+    "sweep_button": "Varrer",
+    "sweep_caveat": "Importa a chave para assinar uma transação que move todos os seus fundos para o seu endereço. A chave permanece na carteira com saldo zero.",
+    "sweep_dest_label": "Enviar fundos varridos para",
+    "sweep_dest_new": "Novo endereço blindado (recomendado)",
+    "sweep_done": "Concluído — fundos varridos para o seu endereço.",
+    "sweep_to": "Varrido para:",
+    "sweep_toggle": "Varrer para minha carteira (não manter a chave)",
+    "sweep_tx": "Transação:",
     "syncing": "Sincronizando...",
     "t_address": "Endereço T",
     "t_addresses": "Endereços T",

res/lang/ru.json

@@ -1202,6 +1202,14 @@
     "submitting_transaction": "Отправка транзакции...",
     "success": "Успешно",
     "summary": "Итоги",
+    "sweep_button": "Перевести",
+    "sweep_caveat": "Импортирует ключ, чтобы подписать одну транзакцию, переводящую все его средства на ваш адрес. Ключ остаётся в кошельке с нулевым балансом.",
+    "sweep_dest_label": "Отправить переведённые средства на",
+    "sweep_dest_new": "Новый экранированный адрес (рекомендуется)",
+    "sweep_done": "Готово — средства переведены на ваш адрес.",
+    "sweep_to": "Переведено на:",
+    "sweep_toggle": "Перевести в мой кошелёк (не сохранять ключ)",
+    "sweep_tx": "Транзакция:",
     "syncing": "Синхронизация...",
     "t_address": "T-адрес",
     "t_addresses": "T-адреса",

res/lang/zh.json

@@ -1202,6 +1202,14 @@
     "submitting_transaction": "正在提交交易...",
     "success": "成功",
     "summary": "摘要",
+    "sweep_button": "归集",
+    "sweep_caveat": "导入密钥以签署一笔将其所有资金转移到您地址的交易。密钥将保留在钱包中，余额为零。",
+    "sweep_dest_label": "将归集资金发送到",
+    "sweep_dest_new": "新的屏蔽地址（推荐）",
+    "sweep_done": "完成 — 资金已归集到您的地址。",
+    "sweep_to": "归集到：",
+    "sweep_toggle": "归集到我的钱包（不保留密钥）",
+    "sweep_tx": "交易：",
     "syncing": "同步中...",
     "t_address": "T 地址",
     "t_addresses": "T 地址",