Persist wallets as watch-only across sessions; re-enter seed to spend

Closing the browser without 'Save to device' used to wipe the wallet entirely.
Now every wallet's account xpub is mirrored to a durable localStorage directory
(never the seed), so it survives a session wipe as a watch-only entry — you keep
seeing balance and history, and re-enter the seed to spend again.

- Durable account directory: saveDirectory() mirrors {id,label,xpub} for every
  account; restore falls back to it as watch-only when there's no session/vault.
- Instant view: a full wallet also caches under its xpub key, so the downgraded
  watch-only shows balance/history immediately (no rescan). Verified round-trip.
- Re-enter seed to spend: the Send tab (now shown for watch-only) and Settings
  prompt for the recovery phrase / xprv; it must derive to this wallet's xpub
  (verified via accountXpubFor — wrong seed/passphrase rejected), with an option
  to Save to device at the same time. Upgrade is in place (id/label/cache kept).
- Vault merge now dedupes by xpub so saved + non-saved wallets coexist without
  duplicates.

Privacy note: the xpub now persists by default (someone with device access can
see balance/history without the seed); 'Remove' clears it.

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

1 files changed, 13 insertions, 0 deletions

diff --git a/src/i18n.js b/src/i18n.js
index e3341a7..d36f301 100644
--- a/src/i18n.js
+++ b/src/i18n.js
@@ -47,6 +47,18 @@ const STR = {
     watchOnlyAdd: 'Add watch-only',
     watchOnlyDesc: 'Watch any wallet from its account public key. You can receive and view balance and history, but not send.',
     watchOnlyNote: 'This is a watch-only wallet. You can receive and view, but you cannot send.',
+    loadSeedTitle: 'Load recovery phrase',
+    loadSeedDesc: "Enter this wallet's recovery phrase (or private key) to spend from it — it must match this wallet.",
+    loadSeedBtn: 'Load recovery phrase',
+    seedPlaceholder: 'Recovery phrase or xprv',
+    bip39PassphraseOpt: 'BIP39 passphrase (optional)',
+    alsoSaveDevice: 'Also save to this device',
+    enterSeedToSpend: 'Enter your recovery phrase.',
+    seedMismatch: "That recovery phrase doesn't match this wallet.",
+    seedNeedsPrivate: "That's a public key — enter the recovery phrase or private key to spend.",
+    seedInvalid: 'Not a valid recovery phrase or key.',
+    watchOnlySendTitle: 'Load your seed to send',
+    watchOnlySendDesc: "You're viewing this wallet without its seed, so you can't spend yet. Load your recovery phrase to send.",
     watchXpubLabel: 'Account xpub or zpub',
     labelOptional: 'Label (optional)',
     walletLabelN: 'Wallet {n}',
@@ -85,6 +97,7 @@ const STR = {
     wordN: 'Word #{n}',
     reenterPassphrase: 'Re-enter passphrase',
     back: '← Back',
+    cancel: 'Cancel',
     openWallet: 'Open wallet',
     wordsMismatch: 'Those words don’t match your phrase. Check your backup.',
     passphraseMismatch: 'That passphrase doesn’t match the one you entered.',