rfc-003: remove timeout from RoleSpec, it's an adapter concern

RoleSpec now has exactly 3 fields: adapter, prompt, meta.
Timeout belongs to adapter config — different timeouts = different adapter instances.

Refs #245
小橘 🍊（NEKO Team）

docs/rfc-003-agent-config-layer.md

@@ -82,7 +82,7 @@ const workflow: WorkflowSpec<MyMeta> = {
   roles: {
     architect: { adapter: cursorAdapter,  prompt: architectPrompt, meta: architectSchema },
     coder:     { adapter: createCursorAdapter({ model: "claude-sonnet-4", timeout: 600 }), prompt: coderPrompt, meta: coderSchema },
-    reviewer:  { adapter: hermesAdapter,  prompt: reviewPrompt,    meta: reviewSchema, timeout: "60s" },
+    reviewer:  { adapter: hermesAdapter,  prompt: reviewPrompt,    meta: reviewSchema },
     deployer:  { adapter: hermesAdapter,  prompt: deployPrompt,    meta: deploySchema },
   },
   moderator,
@@ -162,7 +162,6 @@ type RoleSpec<M> = {
   adapter: AgentFn;
   prompt: PromptInput;
   meta: Schema<M>;
-  timeout: string | null;
 };
 ```
 
@@ -170,22 +169,20 @@ Static prompts cover simple cases. Dynamic prompts (functions) are needed when t
 
 ### Timeout Resolution
 
-Two-layer: adapter default + role override.
+Timeout is an **adapter concern**, not a role concern. Roles define *what to do* (prompt + schema); adapters define *how to do it* (tool, model, timeout).
 
-1. Adapter instance carries its default timeout (set at creation or from default export)
-2. Role definition can override for specific scenarios
+When different roles need different timeouts, create separate adapter instances:
 
 ```ts
 import { cursorAdapter, createCursorAdapter } from "@uncaged/nerve-adapter-cursor";
 
-// cursorAdapter has built-in default (300s)
-// Or create with custom timeout:
-const longRunAdapter = createCursorAdapter({ model: "auto", timeout: 600 });
+const fastCursor = createCursorAdapter({ model: "auto", timeout: 60 });
+const slowCursor = createCursorAdapter({ model: "auto", timeout: 600 });
 
-// Role override — review is faster
-reviewer: { adapter: cursorAdapter, ..., timeout: "60s" }
-// coder uses adapter default (300s)
-coder: { adapter: cursorAdapter, ... }
+roles: {
+  reviewer: { adapter: fastCursor, prompt: reviewPrompt, meta: reviewSchema },
+  coder:    { adapter: slowCursor, prompt: coderPrompt,  meta: coderSchema },
+}
 ```
 
 ### No Runtime Fallback