refactor!: remove deprecated Agent types, introduce Adapter-first API

BREAKING CHANGES:
- Remove AgentFn, AgentFnResult, AgentBinding from workflow-protocol
- Remove wrapAgentAsAdapter from workflow-util-agent
- workflowAsAgent → workflowAdapter (old name kept as deprecated re-export)

New APIs:
- createTextAdapter(producer) — bridges text-producing functions to AdapterFn
- TextProducerFn, TextAdapterResult types
- workflowAdapter() — direct AdapterFn for child workflow delegation

All agent packages (cursor, hermes, llm) now return AdapterFn directly,
no wrapping needed. Bundle entries simplified accordingly.

小橘 🍊（NEKO Team）

packages/workflow-template-develop/bundle-entry.ts

@@ -6,7 +6,6 @@
 import { createCursorAgent } from "@uncaged/workflow-agent-cursor";
 import { createWorkflow } from "@uncaged/workflow-runtime";
 import { optionalEnv, requireEnv } from "@uncaged/workflow-util";
-import { wrapAgentAsAdapter } from "@uncaged/workflow-util-agent";
 import { buildDevelopDescriptor, developWorkflowDefinition } from "./src/index.js";
 
 const llmProvider = {
@@ -18,7 +17,7 @@ const llmProvider = {
   model: optionalEnv("WORKFLOW_LLM_MODEL", "qwen-plus"),
 };
 
-const agent = createCursorAgent({
+const adapter = createCursorAgent({
   command: requireEnv("WORKFLOW_CURSOR_COMMAND", "set WORKFLOW_CURSOR_COMMAND (e.g. cursor-agent)"),
   model: optionalEnv("WORKFLOW_CURSOR_MODEL"),
   timeout: optionalEnv("WORKFLOW_CURSOR_TIMEOUT")
@@ -28,8 +27,6 @@ const agent = createCursorAgent({
   llmProvider,
 });
 
-const adapter = wrapAgentAsAdapter(agent);
-
 const wf = createWorkflow(developWorkflowDefinition, { adapter, overrides: null });
 
 export const descriptor = buildDevelopDescriptor();