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.

crates/aether-data/runtime/src/backend/mod.rs

@@ -32,9 +32,9 @@ pub use mysql::MysqlBackend;
 pub use postgres::PostgresBackend;
 pub use read::DataReadRepositories;
 pub use referrals::{
-    ReferralAdminStats, ReferralDataState, ReferralMutationStatus, ReferralRelationshipListQuery,
-    ReferralRelationshipRecord, ReferralRewardConfig, ReferralRewardListQuery,
-    ReferralRewardRecord, ReferralUserDashboard,
+    ReferralAdminStats, ReferralDataState, ReferralMutationStatus, ReferralReconciliationSummary,
+    ReferralRelationshipListQuery, ReferralRelationshipRecord, ReferralRewardConfig,
+    ReferralRewardListQuery, ReferralRewardRecord, ReferralUserDashboard,
 };
 #[cfg(feature = "sqlite")]
 pub use sqlite::SqliteBackend;
@@ -52,6 +52,11 @@ enum SqlBackendRef<'a> {
     Mysql(&'a MysqlBackend),
     #[cfg(feature = "sqlite")]
     Sqlite(&'a SqliteBackend),
+    // Keep the reference lifetime represented when this crate is built without
+    // any SQL driver features.  The no-driver build still exposes the
+    // maintenance facade, but has no concrete backend variant to carry `'a`.
+    #[cfg(not(any(feature = "postgres", feature = "mysql", feature = "sqlite")))]
+    Disabled(std::marker::PhantomData<&'a ()>),
 }
 
 #[derive(Debug, Clone, Default)]