refactor(workflow): migrate downstream packages to workflow-runtime (Phase 2+3)

- Verify createWorkflow in runtime has zero I/O imports
- Migrate agent-cursor, agent-hermes to pure workflow-runtime dependency
- Migrate agent-llm, util-agent, templates to dual dependency
  (runtime for types, engine for CAS/merkle/buildDescriptor)
- All 377 tests passing

Refs #121, relates #123 #124

packages/workflow-template-develop/__tests__/develop-template.test.ts

@@ -5,7 +5,7 @@ import {
   type RoleStep,
   START,
   validateWorkflowDescriptor,
-} from "@uncaged/workflow";
+} from "@uncaged/workflow-runtime";
 import { buildDevelopDescriptor } from "../src/descriptor.js";
 import { developModerator } from "../src/index.js";
 import type { CommitterMeta, PlannerMeta } from "../src/roles/index.js";