feat(llm): route adapters by provider

examples/echo-agent/cordis.yml

@@ -32,6 +32,7 @@
 - id: stdio-agent
   name: '@deepseek-ai/dsh-stdio-agent'
   config:
+    provider: mock
     model: mock-echo
     persona: 'You are echo-agent, a demo agent.'
     welcome: 'echo-agent ready. Type a message ("echo <text>" triggers the tool).'

examples/echo-agent/src/mock-llm.ts

@@ -55,5 +55,5 @@ export const name = 'mock-llm'
 export const inject = ['llm']
 
 export function apply(ctx: Context) {
-  ctx.llm.registerAdapter(['mock-echo'], new MockEchoAdapter())
+  ctx.llm.registerAdapter(['mock'], new MockEchoAdapter())
 }