Add optional password-encrypted persistence for full accounts

Per-account "Save on this device" encrypts a seed account into a
localStorage vault (scrypt KDF + XChaCha20-Poly1305 via @noble), so it
survives a browser close. On reopen, a vault prompt unlocks all saved
wallets with the password (or "Use another wallet" to skip). Default
stays session-only; the password is held only in memory for the session
and re-encrypts on save/forget. Wrong password fails closed (AEAD).
Adds @noble/ciphers dependency. New strings translated across all 19
locales.

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

1 files changed, 0 insertions, 0 deletions

diff --git a/bun.lockb b/bun.lockb
index 69a0668..e7c5304 100755
--- a/bun.lockb
+++ b/bun.lockb