Replace the audit record with chained audit events

Implemented-By: OpenCode session (model recorded in docs/implementer-log.md)

crates/proto/tests/strict.rs

@@ -89,10 +89,12 @@ fn envelopes_reject_unknown_keys_at_every_depth() {
 #[test]
 fn audit_records_reject_unknown_keys_at_every_depth() {
     for (i, line) in fixture("records/audit.jsonl").lines().enumerate() {
-        // The record and its decision: two objects.
+        // The record and its event: two objects. Decision and approval events also hold an
+        // outcome object.
+        let want = if line.contains("\"outcome\"") { 3 } else { 2 };
         assert_eq!(
             check::<AuditRecord>(&format!("audit.jsonl:{}", i + 1), line),
-            2
+            want
         );
     }
 }