monero-wallet-rpc bootstrap broken on api (invalid password + ringdb perms); restore PAYMENT_REQUIRE_NATIVE

[Svaag]

monero-wallet-rpc on api won't start, which kept XMR un-ready and took hyrule-cloud down (mitigated by temporarily setting PAYMENT_REQUIRE_NATIVE=false in #255).

Symptoms (journalctl -u monero-wallet-rpc)

1. (resolved) failed to parse view key secret key — the xmr_viewkey Vault secret was missing; operator restored it.
2. Wallet initialization failed: invalid password — the hyrule-cloud-monero-restore-wallet ExecStartPre restores via --generate-from-json, then the RPC opens with --password ${MONERO_WALLET_RPC_PASSWORD}. These don't match (Vault secret mismatch, or a stale wallet file from a prior restore with a different password is being reopened).
3. Failed to initialize ringdb: ... Permission denied: "/home/hyrule/.shared-ringdb" — the ringdb path isn't writable by the hyrule user.

Fix

• Make the restore-JSON password == MONERO_WALLET_RPC_PASSWORD (single Vault source); or have the restore step delete any stale wallet file so it always restores fresh with the current password.
• Ensure /home/hyrule/.shared-ringdb (or a configured ringdb dir) is owned/writable by hyrule (or pass --shared-ringdb-dir to a writable path).
• Add a health/readiness probe for monero-wallet-rpc so this is caught before it blocks hyrule-cloud.

After fix

Restore PAYMENT_REQUIRE_NATIVE=true (revert #255) and re-apply playbook=cloud — confirm native XMR is ready again. Relates to #217.