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/vectord/src/autotune.rs

@@ -28,7 +28,7 @@ use aibridge::client::AiClient;
 use catalogd::registry::Registry as CatalogRegistry;
 
 use crate::embedding_cache::EmbeddingCache;
-use crate::harness;
+use crate::harness::{self, HarnessStore};
 use crate::hnsw::HnswStore;
 use crate::index_registry::IndexRegistry;
 use crate::jobs::JobTracker;
@@ -128,7 +128,7 @@ fn pick_winner(trials: &[Trial], min_recall: f32) -> Option<&Trial> {
 #[allow(clippy::too_many_arguments)]
 pub async fn run_autotune(
     req: AutotuneRequest,
-    store: &Arc<dyn ObjectStore>,
+    _store: &Arc<dyn ObjectStore>,
     catalog: &CatalogRegistry,
     ai_client: &AiClient,
     embedding_cache: &EmbeddingCache,
@@ -136,6 +136,7 @@ pub async fn run_autotune(
     index_registry: &IndexRegistry,
     trial_journal: &TrialJournal,
     promotion_registry: &PromotionRegistry,
+    harness_store: &HarnessStore,
     _job_tracker: &JobTracker,
 ) -> Result<AutotuneResult, String> {
     let t0 = std::time::Instant::now();
@@ -146,8 +147,11 @@ pub async fn run_autotune(
     }
     let _ = catalog; // reserved for future audit emission
 
-    // Load the harness once, compute ground truth once.
-    let mut harness_set = harness::EvalSet::load(store, &req.harness)
+    // Load the harness once, compute ground truth once. Harness resolves
+    // to the index's bucket via HarnessStore, with primary as fallback for
+    // pre-federation evals.
+    let mut harness_set = harness_store
+        .load_for_index(&req.index_name, &req.harness)
         .await
         .map_err(|e| format!("load harness: {e}"))?;
 
@@ -160,7 +164,7 @@ pub async fn run_autotune(
         harness::compute_ground_truth(&mut harness_set, &embeddings, ai_client)
             .await
             .map_err(|e| format!("ground truth: {e}"))?;
-        harness_set.save(store).await.ok();
+        harness_store.save(&harness_set).await.ok();
     }
 
     let (grid, rejected) = sanitize_grid(req.grid.clone().unwrap_or_else(default_grid));