Intent of turnStarted calls sendMessage on the agent|occurrence=1, turnStarted passes the dispatching client id to sendMessage|occurrence=1, +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
    
    agentSideEffects.test|title=AgentSideEffects handleAction — session/ 4 tests
    
    mocha:v1|namespace=vscode@05c208e9e28d8c1c723fa08f85e2b7a96092e8e5|file=vs/platform/agentHost/test/node/agentSideEffects.test|title=AgentSideEffects handleAction — session/turnStarted calls sendMessage on the agent|occurrence=1 Introduced here
    
    mocha:v1|namespace=vscode@05c208e9e28d8c1c723fa08f85e2b7a96092e8e5|file=vs/platform/agentHost/test/node/agentSideEffects.test|title=AgentSideEffects handleAction — session/turnStarted parses protocol attachment URI strings before passing them to the agent|occurrence=1 Introduced here
    
    mocha:v1|namespace=vscode@05c208e9e28d8c1c723fa08f85e2b7a96092e8e5|file=vs/platform/agentHost/test/node/agentSideEffects.test|title=AgentSideEffects handleAction — session/turnStarted passes protocol selection attachment range straight through to the agent|occurrence=1 Introduced here
    
    mocha:v1|namespace=vscode@05c208e9e28d8c1c723fa08f85e2b7a96092e8e5|file=vs/platform/agentHost/test/node/agentSideEffects.test|title=AgentSideEffects handleAction — session/turnStarted passes the dispatching client id to sendMessage|occurrence=1 Introduced here