Separate handler from spec in OperationRegistry, update pubsub API

- Split OperationRegistry into separate specs and handlers maps
- Add registerSpec(), registerHandler(), getHandler() methods
- register() still accepts IOperationDefinition (backward compatible)
- execute() now requires both spec and handler, throws if missing
- Update @alkdev/pubsub integration for v0.1.0 API:
  - subscribe(type, id) now requires id parameter (use  for all events)
  - publish(type, id, payload) now requires 3 args
  - Events unwrapped from EventEnvelope via .payload
- Update buildCallHandler to use getSpec() + getHandler() separately
- Update subscribe.ts to use getHandler()
- Update buildEnv to use getAllSpecs() instead of list()
- Update scanner to validate against OperationSpecSchema
- Update from_mcp and from_openapi to use OperationSpec & { handler } types
- Remove OperationDefinitionSchema from public exports
- Add 7 new registry tests for handler separation

src/index.ts

@@ -1,4 +1,4 @@
-export { OperationType, OperationContextSchema, OperationDefinitionSchema, OperationSpecSchema, AccessControlSchema, ErrorDefinitionSchema } from "./types.js";
+export { OperationType, OperationContextSchema, OperationSpecSchema, AccessControlSchema, ErrorDefinitionSchema } from "./types.js";
 export type { IOperationDefinition, OperationHandler, SubscriptionHandler, Identity, OperationEnv, OperationContext, OperationSpec, AccessControl, ErrorDefinition } from "./types.js";
 export { OperationRegistry } from "./registry.js";
 export { formatValueErrors, assertIsSchema, validateOrThrow, collectErrors } from "./validation.js";