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-protocol/src/index.ts

@@ -12,10 +12,7 @@ export type {
   AdapterBinding,
   AdapterFn,
   AdvanceOutcome,
-  AgentBinding,
   AgentContext,
-  AgentFn,
-  AgentFnResult,
   CasStore,
   ExtractFn,
   ExtractResult,

packages/workflow-protocol/src/types.ts

@@ -143,18 +143,6 @@ export type ExtractFn = <T extends Record<string, unknown>>(
   contentHash: string,
 ) => Promise<ExtractResult<T>>;
 
-/** @deprecated Use {@link AdapterFn} instead. Will be removed in a future release. */
-export type AgentFnResult = string | { output: string; childThread: string | null };
-
-/** @deprecated Use {@link AdapterFn} instead. Will be removed in a future release. */
-export type AgentFn = (ctx: AgentContext) => Promise<AgentFnResult>;
-
-/** @deprecated Use {@link AdapterBinding} instead. Will be removed in a future release. */
-export type AgentBinding = {
-  agent: AgentFn;
-  overrides: Partial<Record<string, AgentFn>> | null;
-};
-
 // ── Adapter (replaces Agent) ────────────────────────────────────────
 
 export type RoleResult<T> = { meta: T; childThread: string | null };