PayPal client_secret (and any secret-named integration field) was stored
plaintext in integrations.config, unlike Stripe/door which use the
AES-256-GCM vault. A DB read or backup leaked it in cleartext.
- lib/secrets/vault.ts: canonical generic storeSecret/readSecret +
isSecretConfigField (the proven Stripe vault logic, generalized).
- saveIntegration: secret-named fields go to the vault, only a *_ref is
kept in config; blank submit preserves the ref (write-only like
Stripe); legacy plaintext auto-migrates into the vault on next save.
- paypal/sync reads client_secret from the vault, transitional fallback
to legacy plaintext until the next save.
- Docs updated (API_REFERENCE, ARCHITECTURE 10.3). 502 tests.
Moheeb Zara
504586fdcd