Persist exact workflow revisions additively

crates/buzz-db/src/runtime/migration.rs

@@ -702,7 +702,7 @@ mod postgres_tests {
         let mut migrations: Vec<_> = MIGRATOR.iter().collect();
         migrations.sort_by_key(|migration| migration.version);
 
-        assert_eq!(migrations.len(), 44);
+        assert_eq!(migrations.len(), 45);
         assert_eq!(migrations[0].version, 1);
         assert_eq!(&*migrations[0].description, "initial schema");
         assert!(migrations[0]
@@ -1165,6 +1165,35 @@ mod postgres_tests {
         assert!(heartbeat_vacuum.contains("vacuum_truncate = false"));
         assert!(desired_schema.contains("vacuum_truncate = false"));
 
+        // Workflow revision capture is additive: nullable 32-byte event IDs on
+        // both the materialized definition and run, with identical fresh-schema
+        // constraints and no backfill hidden in startup migration state.
+        assert_eq!(migrations[44].version, 45);
+        let workflow_revision_binding = migrations[44].sql.as_str();
+        assert!(workflow_revision_binding.contains("ALTER TABLE workflows"));
+        assert!(workflow_revision_binding.contains("ALTER TABLE workflow_runs"));
+        assert!(workflow_revision_binding.contains("octet_length(definition_event_id) = 32"));
+        assert!(!workflow_revision_binding.contains("UPDATE workflows"));
+        let revision_guard = |sql: &str| {
+            let start = sql
+                .find("CREATE FUNCTION invalidate_workflow_revision()")
+                .unwrap();
+            let end = sql[start..]
+                .find("FOR EACH ROW EXECUTE FUNCTION invalidate_workflow_revision();")
+                .unwrap();
+            sql[start..start + end].to_owned()
+        };
+        assert_eq!(
+            revision_guard(workflow_revision_binding),
+            revision_guard(desired_schema)
+        );
+        assert_eq!(
+            desired_schema
+                .matches("octet_length(definition_event_id) = 32")
+                .count(),
+            2
+        );
+
         // pgschema intentionally reconciles DDL, not seed DML or table storage
         // parameters. Its post-apply reconciliation must restore and verify
         // both parts of the live heartbeat contract for fresh bootstraps.