Limit agent execution by tokens consumed

Stop agent execution after consuming a certain number of tokens

Also check out:
https://devblogs.microsoft.com/agent-framework/governance-at-the-speed-of-agents-microsoft-agent-framework-and-agent-governance-toolkit-better-together/
https://github.com/microsoft/agent-governance-toolkit/blob/main/agent-governance-dotnet/src/AgentGovernance/AgentGovernance.csproj

To see if it already solves the problem.