Control-plane pivot: Phase 38-44 plan + bot scaffold

Direction shift 2026-04-22: docs/CONTROL_PLANE_PRD.md becomes the
long-horizon architecture target. Existing Lakehouse (docs/PRD.md,
Phases 0-37) is preserved as the reference implementation and first
consumer. New 6-layer architecture:

  L1 Universal API /v1/chat /v1/usage /v1/sessions /v1/tools /v1/context
  L2 Routing & Policy Engine (rules, fallback chains, cost gating)
  L3 Provider Adapter Layer (Ollama + OpenRouter + Gemini + Claude)
  L4 Knowledge + Memory + Playbooks (already built)
  L5 Execution Loop (scenarios + bot/cycle.ts instances)
  L6 Observability + token accounting

Phases 38-44 sequenced with detailed per-phase specs in the PRD.
Current scope: staffing domain (synthetic workers_500k, contracts,
emails, SMS, playbooks). DevOps (Terraform/Ansible) is long-horizon
target — architecture-compatible but not current.

Files added:
- docs/CONTROL_PLANE_PRD.md — 6-layer architecture, Phase 38-44
  sequencing with staffing-first Truth Layer + Validation pipeline
- bot/ — manual-only PR bot scaffold. First consumer test-bed for
  /v1/chat (Phase 38). Mem0-aligned ADD/UPDATE/NOOP apply semantics;
  KB feedback loop reads prior cycles on same gap and injects into
  cloud prompt so bot cycles compound like scenario.ts runs do.
- tests/multi-agent/run_stress.ts — the 6-task diverse stress test
  referenced in the previous commit but missing from its staging

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

bot/observer.ts

@@ -0,0 +1,34 @@
+// POST bot cycle outcomes to the observer on :3800 so they accumulate
+// in the KB alongside scenario + autotune events. Non-fatal on failure:
+// the cycle result is also written to disk so observability isn't a
+// single point of failure.
+
+const OBSERVER_URL = process.env.LH_OBSERVER_URL ?? "http://localhost:3800";
+
+export interface BotObserverEvent {
+  source: "bot";
+  cycle_id: string;
+  sig_hash: string;          // stable hash of the gap + proposal for dedup
+  event_kind: string;        // cycle outcome (ok, tests_failed, ...)
+  ok: boolean;
+  staffer_id?: string;       // the model used, e.g. "gpt-oss:120b"
+  turns?: number;            // number of cloud calls this cycle
+  duration_ms?: number;
+  extra?: Record<string, any>;
+}
+
+export async function postEvent(ev: BotObserverEvent): Promise<void> {
+  try {
+    const r = await fetch(`${OBSERVER_URL}/event`, {
+      method: "POST",
+      headers: { "content-type": "application/json" },
+      body: JSON.stringify(ev),
+      signal: AbortSignal.timeout(3000),
+    });
+    if (!r.ok) {
+      console.error(`[bot/observer] ${r.status}: ${await r.text()}`);
+    }
+  } catch (e) {
+    console.error(`[bot/observer] POST failed: ${(e as Error).message}`);
+  }
+}