Add parent seed backup command and API

README.md

@@ -452,6 +452,7 @@ Mutation testing is disabled in the GitHub workflow due to reliability issues an
 - **Backup Your Data:** Regularly back up your encrypted data and checksum files to prevent data loss.
 - **Backup the Settings PIN:** Your settings PIN is stored in the encrypted configuration file. Keep a copy of this file or remember the PIN, as losing it will require deleting the file and reconfiguring your relays.
 - **Protect Your Passwords:** Do not share your master password or seed phrases with anyone and ensure they are strong and unique.
+- **Revealing the Parent Seed:** The `vault reveal-parent-seed` command and `/api/v1/parent-seed` endpoint print your seed in plain text. Run them only in a secure environment.
 - **No PBKDF2 Salt Needed:** SeedPass deliberately omits an explicit PBKDF2 salt. Every password is derived from a unique 512-bit BIP-85 child seed, which already provides stronger per-password uniqueness than a conventional 128-bit salt.
 - **Checksum Verification:** Always verify the script's checksum to ensure its integrity and protect against unauthorized modifications.
 - **Potential Bugs and Limitations:** Be aware that the software may contain bugs and lacks certain features. Snapshot chunks are capped at 50 KB and the client rotates snapshots after enough delta events accumulate. The security of memory management and logs has not been thoroughly evaluated and may pose risks of leaking sensitive information.