Phase 28-36 body of work

Accumulated since a6f12e2 (Phase 21 Rust port + Phase 27 versioning):

- Phase 36: embed_semaphore on VectorState (permits=1) serializes
  seed embed calls — prevents sidecar socket collisions under
  concurrent /seed stress load
- Phase 31+: run_stress.ts 6-task diverse stress scaffolding;
  run_e2e_rated.ts + orchestrator.ts tightening
- Catalog dedupe cleanup: 16 duplicate manifests removed; canonical
  candidates.parquet (10.5MB -> 76KB) + placements.parquet (1.2MB ->
  11KB) regenerated post-dedupe; fresh manifests for active datasets
- vectord: harness EvalSet refinements (+181), agent portfolio
  rotation + ingest triggers (+158), autotune + rag adjustments
- catalogd/storaged/ingestd/mcp-server: misc tightening
- docs: Phase 28-36 PRD entries + DECISIONS ADR additions;
  control-plane pivot banner added to top of docs/PRD.md (pointing
  at docs/CONTROL_PLANE_PRD.md which lands in next commit)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/storaged/src/error_journal.rs

@@ -198,3 +198,92 @@ impl ErrorJournal {
         self.log.file_count().await
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use object_store::memory::InMemory;
+
+    fn mk() -> ErrorJournal {
+        ErrorJournal::new(Arc::new(InMemory::new()))
+    }
+
+    #[tokio::test]
+    async fn append_updates_ring_immediately() {
+        let j = mk();
+        j.append(BucketErrorEvent::new_read("tenant_a", "k1", "timeout")).await;
+        j.append(BucketErrorEvent::new_write("tenant_b", "k2", "denied")).await;
+
+        let recent = j.recent(10).await;
+        assert_eq!(recent.len(), 2);
+        assert_eq!(recent[0].target, "tenant_a");
+        assert_eq!(recent[1].target, "tenant_b");
+    }
+
+    #[tokio::test]
+    async fn load_recent_rehydrates_ring_from_disk() {
+        // Use a shared InMemory store so the second journal reads the first
+        // journal's writes — mirrors gateway restart semantics.
+        let store: Arc<dyn ObjectStore> = Arc::new(InMemory::new());
+        {
+            let j1 = ErrorJournal {
+                log: Arc::new(AppendLog::new(store.clone(), JOURNAL_PREFIX).with_flush_threshold(1)),
+                ring: Arc::new(RwLock::new(VecDeque::with_capacity(RING_CAPACITY))),
+            };
+            j1.append(BucketErrorEvent::new_read("t", "k", "err")).await;
+            j1.flush().await.unwrap();
+        }
+
+        let j2 = ErrorJournal {
+            log: Arc::new(AppendLog::new(store.clone(), JOURNAL_PREFIX)),
+            ring: Arc::new(RwLock::new(VecDeque::with_capacity(RING_CAPACITY))),
+        };
+        assert_eq!(j2.recent(10).await.len(), 0, "fresh ring is empty");
+
+        let loaded = j2.load_recent().await.unwrap();
+        assert_eq!(loaded, 1);
+        assert_eq!(j2.recent(10).await[0].target, "t");
+    }
+
+    #[tokio::test]
+    async fn mark_rescued_updates_most_recent_match() {
+        let j = mk();
+        j.append(BucketErrorEvent::new_read("t1", "k", "err")).await;
+        j.append(BucketErrorEvent::new_read("t2", "k", "err")).await;
+        j.append(BucketErrorEvent::new_read("t1", "k", "err")).await;
+
+        j.mark_rescued_last("t1", "k").await;
+
+        let recent = j.recent(10).await;
+        assert!(!recent[0].rescued, "older t1 event not touched");
+        assert!(!recent[1].rescued, "t2 not touched");
+        assert!(recent[2].rescued, "most recent t1 was rescued");
+    }
+
+    #[tokio::test]
+    async fn health_flags_buckets_with_three_or_more_errors() {
+        let j = mk();
+        for _ in 0..3 { j.append(BucketErrorEvent::new_read("broken", "k", "e")).await; }
+        j.append(BucketErrorEvent::new_read("flaky", "k", "e")).await;
+
+        let h = j.health(60).await;
+        assert_eq!(h.total_errors, 4);
+        assert_eq!(h.per_bucket.get("broken"), Some(&3));
+        assert_eq!(h.per_bucket.get("flaky"), Some(&1));
+        assert!(h.unhealthy_buckets.contains(&"broken".to_string()));
+        assert!(!h.unhealthy_buckets.contains(&"flaky".to_string()));
+    }
+
+    #[tokio::test]
+    async fn filter_by_bucket_returns_chronological_order() {
+        let j = mk();
+        j.append(BucketErrorEvent::new_read("a", "k1", "e")).await;
+        j.append(BucketErrorEvent::new_read("b", "k2", "e")).await;
+        j.append(BucketErrorEvent::new_read("a", "k3", "e")).await;
+
+        let only_a = j.filter(Some("a"), None, 10).await;
+        assert_eq!(only_a.len(), 2);
+        assert_eq!(only_a[0].key, "k1", "oldest first");
+        assert_eq!(only_a[1].key, "k3");
+    }
+}