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/adapters/postgres/src/usage/queries/find_by_id_sql.sql

@@ -221,11 +221,13 @@ SELECT
   usage_settlement_snapshots.billing_rule_id AS settlement_billing_rule_id,
   usage_settlement_snapshots.billing_rule_version AS settlement_billing_rule_version,
   CAST(EXTRACT(EPOCH FROM "usage".created_at) AS BIGINT) AS created_at_unix_ms,
-  GREATEST(
-    COALESCE(NULLIF("usage".updated_at_unix_secs, 0), 0),
-    COALESCE(CAST(EXTRACT(EPOCH FROM usage_settlement_snapshots.finalized_at) AS BIGINT), 0),
-    COALESCE(CAST(EXTRACT(EPOCH FROM "usage".finalized_at) AS BIGINT), 0),
-    CAST(EXTRACT(EPOCH FROM "usage".created_at) AS BIGINT)
+  COALESCE(
+    NULLIF("usage".updated_at_unix_secs, 0),
+    GREATEST(
+      COALESCE(CAST(EXTRACT(EPOCH FROM usage_settlement_snapshots.finalized_at) AS BIGINT), 0),
+      COALESCE(CAST(EXTRACT(EPOCH FROM "usage".finalized_at) AS BIGINT), 0),
+      CAST(EXTRACT(EPOCH FROM "usage".created_at) AS BIGINT)
+    )
   ) AS updated_at_unix_secs,
   CAST(
     EXTRACT(

crates/aether-data/adapters/postgres/src/usage/queries/find_by_request_id_sql.sql

@@ -225,11 +225,13 @@ SELECT
   usage_settlement_snapshots.billing_rule_id AS settlement_billing_rule_id,
   usage_settlement_snapshots.billing_rule_version AS settlement_billing_rule_version,
   CAST(EXTRACT(EPOCH FROM "usage".created_at) AS BIGINT) AS created_at_unix_ms,
-  GREATEST(
-    COALESCE(NULLIF("usage".updated_at_unix_secs, 0), 0),
-    COALESCE(CAST(EXTRACT(EPOCH FROM usage_settlement_snapshots.finalized_at) AS BIGINT), 0),
-    COALESCE(CAST(EXTRACT(EPOCH FROM "usage".finalized_at) AS BIGINT), 0),
-    CAST(EXTRACT(EPOCH FROM "usage".created_at) AS BIGINT)
+  COALESCE(
+    NULLIF("usage".updated_at_unix_secs, 0),
+    GREATEST(
+      COALESCE(CAST(EXTRACT(EPOCH FROM usage_settlement_snapshots.finalized_at) AS BIGINT), 0),
+      COALESCE(CAST(EXTRACT(EPOCH FROM "usage".finalized_at) AS BIGINT), 0),
+      CAST(EXTRACT(EPOCH FROM "usage".created_at) AS BIGINT)
+    )
   ) AS updated_at_unix_secs,
   CAST(
     EXTRACT(

crates/aether-data/adapters/postgres/src/usage/queries/list_recent_usage_audits_prefix.sql

@@ -327,11 +327,13 @@ SELECT
   usage_settlement_snapshots.billing_rule_id AS settlement_billing_rule_id,
   usage_settlement_snapshots.billing_rule_version AS settlement_billing_rule_version,
   CAST(EXTRACT(EPOCH FROM "usage".created_at) AS BIGINT) AS created_at_unix_ms,
-  GREATEST(
-    COALESCE(NULLIF("usage".updated_at_unix_secs, 0), 0),
-    COALESCE(CAST(EXTRACT(EPOCH FROM usage_settlement_snapshots.finalized_at) AS BIGINT), 0),
-    COALESCE(CAST(EXTRACT(EPOCH FROM "usage".finalized_at) AS BIGINT), 0),
-    CAST(EXTRACT(EPOCH FROM "usage".created_at) AS BIGINT)
+  COALESCE(
+    NULLIF("usage".updated_at_unix_secs, 0),
+    GREATEST(
+      COALESCE(CAST(EXTRACT(EPOCH FROM usage_settlement_snapshots.finalized_at) AS BIGINT), 0),
+      COALESCE(CAST(EXTRACT(EPOCH FROM "usage".finalized_at) AS BIGINT), 0),
+      CAST(EXTRACT(EPOCH FROM "usage".created_at) AS BIGINT)
+    )
   ) AS updated_at_unix_secs,
   CAST(
     EXTRACT(

crates/aether-data/adapters/postgres/src/usage/queries/list_usage_audits_prefix.sql

@@ -327,11 +327,13 @@ SELECT
   usage_settlement_snapshots.billing_rule_id AS settlement_billing_rule_id,
   usage_settlement_snapshots.billing_rule_version AS settlement_billing_rule_version,
   CAST(EXTRACT(EPOCH FROM "usage".created_at) AS BIGINT) AS created_at_unix_ms,
-  GREATEST(
-    COALESCE(NULLIF("usage".updated_at_unix_secs, 0), 0),
-    COALESCE(CAST(EXTRACT(EPOCH FROM usage_settlement_snapshots.finalized_at) AS BIGINT), 0),
-    COALESCE(CAST(EXTRACT(EPOCH FROM "usage".finalized_at) AS BIGINT), 0),
-    CAST(EXTRACT(EPOCH FROM "usage".created_at) AS BIGINT)
+  COALESCE(
+    NULLIF("usage".updated_at_unix_secs, 0),
+    GREATEST(
+      COALESCE(CAST(EXTRACT(EPOCH FROM usage_settlement_snapshots.finalized_at) AS BIGINT), 0),
+      COALESCE(CAST(EXTRACT(EPOCH FROM "usage".finalized_at) AS BIGINT), 0),
+      CAST(EXTRACT(EPOCH FROM "usage".created_at) AS BIGINT)
+    )
   ) AS updated_at_unix_secs,
   CAST(
     EXTRACT(

crates/aether-data/adapters/postgres/src/usage/queries/upsert_first_byte_sql.sql

@@ -119,6 +119,10 @@ DO UPDATE SET
 WHERE "usage".billing_status = 'pending'
   AND "usage".status IN ('pending', 'streaming')
   AND "usage".finalized_at IS NULL
+  AND EXCLUDED.updated_at_unix_secs >= COALESCE(
+    NULLIF("usage".updated_at_unix_secs, 0),
+    CAST(EXTRACT(EPOCH FROM "usage".created_at) AS BIGINT)
+  )
 RETURNING
   request_id,
   provider_api_key_id,