Vcwallet 0.8.7 recovery model

- Each Litecoin wallet has a 24-word Vcwallet recovery phrase.
- The phrase encodes the exact existing Litecoin private key, so upgrading an existing wallet does not change its address.
- The phrase is not stored in plaintext. The underlying key remains AES-GCM encrypted locally with the account password.
- If local extension storage is missing, Vcwallet no longer silently generates a replacement Litecoin address. It asks for the recovery phrase.
- New accounts must save the phrase and correctly confirm selected words before the account is finalized.
- Changing a user/admin password requires the matching recovery phrase.
- The lock screen can recover/reset both normal user wallets and the built-in Admin wallet using the matching recovery phrase.
- Existing WIF export/import remains available as an advanced Litecoin interoperability backup.
- This 24-word Vcwallet recovery encoding is Vcwallet-specific; do not assume another wallet app will derive the same address from these words. Use WIF for Litecoin portability.

Security: Never share a recovery phrase, WIF, private key, or password. Anyone with the recovery phrase or WIF controls the funds.
