Enforce Android lifecycle and presentation security (#100)

docs/android/onboarding.md

@@ -14,9 +14,10 @@ by Release shrinking. Certificate validation uses the operating system trust sto
 Local setup generates or imports a private GPG key, verifies its passphrase, creates
 Git and the upstream `.gpg-id`, and commits the configuration. No server, camera,
 or biometric permission is needed. Encrypted prepared keys survive process death;
-passphrases and tokens remain in memory only. Form secrets survive rotation through
-a ViewModel and are excluded from saved-state Bundles. After process death transport
-and passphrase inputs must be entered again.
+passphrases and tokens remain in memory only and are excluded from saved-state
+Bundles. Presentation revocation clears form secrets synchronously, including
+backgrounding, rotation and memory pressure. Pending transport requests are cancelled
+and released; transport and passphrase inputs must be entered again after returning.
 
 HTTPS setup discovers branches with a temporary Rust repository, selects the branch,
 and checks the selected private key against the cloned root recipient policy. Reusing