feat(daemon,cli): RFC-003 Phase 5 — Integration (hot-reload + validate)

- Kernel: rebuild AgentRegistry on config hot-reload, log agent_registry_reload
- Running threads unaffected, new threads use rebuilt registry
- nerve validate: check agent name refs in WorkflowSpec source files
- nerve validate: verify adapter type is known (KNOWN_AGENT_ADAPTER_IDS)
- nerve validate: require extract config when WorkflowSpec agent refs exist
- Tests: kernel reload (mock), validate (missing/valid/extract/adapter)

Closes #239
Ref: #234

packages/core/src/agent-adapter-ids.ts

@@ -0,0 +1,5 @@
+/**
+ * Agent adapter types that have a daemon implementation (RFC-003).
+ * Keep in sync with `packages/daemon` agent factory dispatch.
+ */
+export const KNOWN_AGENT_ADAPTER_IDS = ["echo"] as const;

packages/core/src/index.ts

@@ -36,6 +36,7 @@ export type { Result } from "./result.js";
 export { ok, err } from "./result.js";
 export { parseNerveConfig } from "./parse-nerve-config.js";
 export { isPlainRecord } from "./is-plain-record.js";
+export { KNOWN_AGENT_ADAPTER_IDS } from "./agent-adapter-ids.js";
 
 export type { RoutedSenseOutput } from "./sense-workflow-directive.js";
 export { parseWorkflowTrigger, routeSenseComputeOutput } from "./sense-workflow-directive.js";