Intent of copilotAgent.ts ×2

All 4 exact tests in this concept. Every test is marked by where it enters the hierarchy.

mocha:v1|namespace=vscode@05c208e9e28d8c1c723fa08f85e2b7a96092e8e5|file=vs/ 4 tests
- platform/ 4 tests
  - agentHost/ 4 tests
    
    test/ 4 tests
    
    node/ 4 tests
    
    copilotAgent.test|title=CopilotAgent peer chat create / 3 tests
    
    fork / 3 tests
    
    model+agent / 3 tests
    
    mocha:v1|namespace=vscode@05c208e9e28d8c1c723fa08f85e2b7a96092e8e5|file=vs/platform/agentHost/test/node/copilotAgent.test|title=CopilotAgent peer chat create / fork / model+agent / restore round-trip createChat forks the source chat into a new peer chat and returns the forked chat providerData|occurrence=1 Inherited restore round-trip createChat forks the source chat into a new peer chat and returns the forked chat providerData|occurrence=1
    
    mocha:v1|namespace=vscode@05c208e9e28d8c1c723fa08f85e2b7a96092e8e5|file=vs/platform/agentHost/test/node/copilotAgent.test|title=CopilotAgent peer chat create / fork / model+agent / restore round-trip createChat side chat forks hidden context and filters inherited turns|occurrence=1 Inherited restore round-trip createChat side chat forks hidden context and filters inherited turns|occurrence=1
    
    mocha:v1|namespace=vscode@05c208e9e28d8c1c723fa08f85e2b7a96092e8e5|file=vs/platform/agentHost/test/node/copilotAgent.test|title=CopilotAgent peer chat create / fork / model+agent / restore round-trip createChat side chat preserves a local source turn id while forking from the concrete provider anchor|occurrence=1 Inherited copilotAgent.ts ×4
    
    mocha:v1|namespace=vscode@05c208e9e28d8c1c723fa08f85e2b7a96092e8e5|file=vs/platform/agentHost/test/node/copilotAgent.test|title=CopilotAgent chat surface (IAgentChats) fork delegates to createChat with the fork source|occurrence=1 Inherited copilotAgent.ts ×3