Fold watch-only into Import; support xprv spending import

Home screen is back to two tabs (Create / Import). The Import box now
takes a recovery phrase, an xpub/zpub, or an xprv/zprv:
- mnemonic → full wallet (as before)
- xpub/zpub → watch-only (view/receive, no Send)
- xprv/zprv → full spending wallet with no mnemonic. parseExtendedKey
  classifies + normalizes version bytes; account() derives the BIP84
  path from a master xprv (depth 0) or uses an account-level xprv as-is;
  signing works (only watch-only blocks it). Vault persists xprv accounts
  too; Settings shows an "Imported key" note instead of a recovery card
  and hides Nostr sync (no seed). Public-key export still works.

Note: a seed phrase cannot be derived from an xprv (one-way KDF), so an
xprv wallet has no recovery words by design. New strings in all 19 locales.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

1 files changed, 7 insertions, 2 deletions

diff --git a/src/locales/ko.json b/src/locales/ko.json
index dbe6775..6ef7917 100644
--- a/src/locales/ko.json
+++ b/src/locales/ko.json
@@ -205,5 +205,10 @@
   "unlockSavedDesc": "이 기기에 저장된 지갑을 열려면 비밀번호를 입력하세요.",
   "unlock": "잠금 해제",
   "useAnotherWallet": "다른 지갑 사용",
-  "save": "저장"
-}
+  "save": "저장",
+  "importLabel": "복구 문구 또는 키",
+  "importPlaceholder": "12개 또는 24개 단어, 또는 xpub / xprv",
+  "invalidImport": "유효한 복구 문구, xpub 또는 xprv가 아닙니다.",
+  "importedKey": "가져온 키",
+  "importedKeyNote": "이 지갑은 확장 개인 키에서 가져왔으므로 복구 문구가 없습니다. 지갑을 유지하려면 그 키 자체를 백업하세요."
+}
\ No newline at end of file