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>

mcp-server/index.ts

@@ -26,17 +26,31 @@ const MODE = process.env.MCP_TRANSPORT || "http"; // "stdio" or "http"
 // Active trace for the current request — set per-request in the HTTP handler
 let activeTrace: ReturnType<typeof startTrace> | null = null;
 
-async function api(method: string, path: string, body?: any) {
-  const t0 = Date.now();
-  const resp = await fetch(`${BASE}${path}`, {
-    method,
-    headers: body ? { "Content-Type": "application/json" } : {},
-    body: body ? JSON.stringify(body) : undefined,
-  });
-  const text = await resp.text();
-  const ms = Date.now() - t0;
-  let parsed: any;
-  try { parsed = JSON.parse(text); } catch { parsed = { raw: text, status: resp.status }; }
+async function api(method: string, path: string, body?: any, retries = 2) {
+  for (let attempt = 0; attempt <= retries; attempt++) {
+    try {
+      const t0 = Date.now();
+      const resp = await fetch(`${BASE}${path}`, {
+        method,
+        headers: body ? { "Content-Type": "application/json" } : {},
+        body: body ? JSON.stringify(body) : undefined,
+      });
+      const text = await resp.text();
+      const ms = Date.now() - t0;
+      let parsed: any;
+      try { parsed = JSON.parse(text); } catch { parsed = { raw: text, status: resp.status }; }
+      return parsed;
+    } catch (e: any) {
+      if (attempt === retries) throw e;
+      if (e.message?.includes("socket connection was closed") || e.message?.includes("ECONNREFUSED")) {
+        await Bun.sleep(500 * (attempt + 1));
+        continue;
+      }
+      throw e;
+    }
+  }
+  throw new Error("unreachable");
+}
 
   // Trace the call if we have an active trace
   if (activeTrace) {