[factory] p12: node-targeted placement + reject-and-reconcile

CHANGELOG.md

@@ -18,6 +18,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `agent-relay fleet serve|nodes|status` runs a fleet node sidecar and inspects registered nodes, and the broker MCP surface adds `query_nodes` and `spawn` tools.
 - `@agent-relay/config` `CLI_AUTH_CONFIG` adds an `xai` provider (Grok CLI): `grok login --device-auth` device-code connect, `~/.grok/auth.json` credential capture, and the official x.ai installer as the sandbox fallback — so cloud sandboxes can authenticate the `grok` harness from a connected account instead of an API key.
 - `@agent-relay/sdk` wires the durable delivery surface to the Relaycast backend: `inbox.list`, `inbox.subscribe`, `inbox.ack/fail/defer`, and `deliveries.ack/fail/defer` now use the hosted delivery ledger, agent-scoped capabilities report `serverDeliveryState: true`, and `DeliveryRunner` works against Relaycast-backed inbox items.
+- `@agent-relay/sdk` adds `placement.spawn({ capability, node?, repo? })` — node-targeted/`self`/least-eligible placement that gates on advertised capability and repo-key map, queues with a bounded TTL until an eligible live node appears, and surfaces queue/fail visibility through `onReconcile` events. A `spawn:<cli>` capability pins the broker harness — a mismatched `input.cli` is rejected — and the exported `RelayPlacementError` reports `capability_mismatch` / `placement_queue_full` / `placement_ttl_expired` / `unmapped_repo`.
 - Two-node fleet E2E (`tests/e2e/fleet`, `npm run test:e2e`, `Fleet E2E` CI workflow): boots a real relaycast engine plus two `agent-relay fleet serve` nodes (real Rust broker + sidecar each) and asserts the live control wire — boot/register (real broker `Authorization: Bearer` node auth), negative auth, capability-filtered roster, cross-node action dispatch + ack, declarative trigger fire-once with loop guard, end-to-end spawn completion (token mint+inject), capability-routed + least-loaded + resume placement, `capability_mismatch` failure, in-flight reschedule on node death + restart reconcile, and bounded-mailbox TTL dead-letter.
 
 ### Changed

packages/sdk/src/messaging/index.ts

@@ -1,3 +1,7 @@
 export * from './types.js';
 export * from './normalize.js';
-export { RelaycastMessagingClient, type RelaycastMessagingOptions } from './relaycast.js';
+export {
+  RelayPlacementError,
+  RelaycastMessagingClient,
+  type RelaycastMessagingOptions,
+} from './relaycast.js';