feat(security): harden gateway boundaries and usage policies

Consolidate subscription usage policy enforcement, privacy-safe persistence, and gateway security hardening into one reviewable change.

Includes bounded HTTP and execution envelopes, header and protocol guards, DNS and relay validation, authentication and secret projection hardening, secure backup/install paths, and regression coverage.

apps/aether-gateway/src/state/mod.rs

@@ -6,6 +6,8 @@ mod app;
 mod bootstrap_admin;
 mod cache;
 mod catalog;
+mod catalog_credentials;
+mod catalog_proxy;
 mod core;
 mod cors;
 mod integrations;
@@ -23,7 +25,8 @@ pub(crate) use self::admin_types::{
     AdminBillingPresetApplyResult, AdminBillingRuleRecord, AdminBillingRuleWriteInput,
     AdminPaymentCallbackRecord, AdminSecurityBlacklistEntry, AdminWalletPaymentOrderRecord,
     AdminWalletRefundRecord, AdminWalletTransactionRecord, BillingPlanRecord,
-    BillingPlanWriteInput, PaymentGatewayConfigRecord, PaymentGatewayConfigWriteInput,
+    BillingPlanWriteInput, PaymentGatewayConfigCasWriteInput, PaymentGatewayConfigRecord,
+    PaymentGatewayConfigWriteInput, PaymentGatewaySecretCasUpdate,
     UserDailyQuotaAvailabilityRecord, UserPlanEntitlementRecord,
 };
 pub use self::app::AppState;
@@ -42,10 +45,15 @@ pub(crate) use self::oauth::{
     provider_transport_context_allows_credential_rotation, AgentIdentityAuthConfigFence,
     CodexRuntimeOAuthObservation, ProviderTransportCredentialFence,
 };
+pub(crate) use self::proxy::{
+    decrypt_or_migrate_proxy_tunnel_psk, decrypt_or_migrate_proxy_tunnel_psk_binding,
+    unavailable_proxy_snapshot,
+};
 pub(crate) use self::types::{
     AdminWalletMutationOutcome, GatewayAdminPaymentCallbackView, GatewayUserPreferenceView,
     GatewayUserSessionView, LocalExecutionRuntimeMissDiagnostic, LocalMutationOutcome,
     LocalProviderDeleteTaskState,
 };
+pub(crate) use self::video::VideoTaskRouteAccess;
 use super::provider_transport::provider_transport_snapshot_looks_refreshed;
 pub(crate) use super::provider_transport::ProviderTransportSnapshotCacheKey;