feat(core): add agent execution context

packages/core/agent-loop/tests/coverage-edges.spec.ts

@@ -6,6 +6,7 @@ import type { SessionEvent } from '@deepseek-ai/dsh-session'
 import SystemPrompt from '@deepseek-ai/dsh-system-prompt'
 import ToolRegistry, { defineTool } from '@deepseek-ai/dsh-tools'
 import AgentRegistry, { AgentId } from '@deepseek-ai/dsh-agent'
+import AgentExecutionProvider from '@deepseek-ai/dsh-agent-execution'
 import AgentLoop, { ReactLoopAgent } from '@deepseek-ai/dsh-agent-loop'
 import { MockAdapter, textResponse, toolCallResponse } from './mock-adapter.ts'
 
@@ -16,6 +17,7 @@ async function harness(adapter: MockAdapter) {
   await ctx.plugin(SystemPrompt)
   await ctx.plugin(ToolRegistry)
   await ctx.plugin(AgentRegistry)
+  await ctx.plugin(AgentExecutionProvider)
   await ctx.plugin(AgentLoop, { agents: [] })
   ctx.llm.registerAdapter(['mock'], adapter)
   return ctx