refactor: all-agentic architecture — roles as pure data, agent binding at runtime

BREAKING: Major architecture change.

- RoleDefinition = pure data (systemPrompt + schema + dryRunMeta)
- AgentFn = (ctx: ThreadContext) => Promise<string>, reads ctx.currentRole
- WorkflowDefinition decoupled from agents, bound via AgentBinding at runtime
- createWorkflow(def, binding, extract) replaces createRoleModerator
- Meta extraction moved into engine loop
- Delete workflow-util-role package (createRole, decorators, extract all gone)
- Role packages become pure data exports
- Agent packages updated to single-arg AgentFn

小橘 <xiaoju@shazhou.work>

packages/workflow-agent-llm/tsconfig.json

@@ -6,5 +6,5 @@
     "composite": true
   },
   "include": ["src/**/*.ts"],
-  "references": [{ "path": "../workflow" }, { "path": "../workflow-util-role" }]
+  "references": [{ "path": "../workflow" }]
 }