Add evidence-first Agent Framework incident triage sample

[balajibashyam]

Summary

Adds a verified .NET 10 companion sample for the
Microsoft Agent Framework Tutorial in C#: Build a Tool-Using AI Agent.

What's included

• New sample: dotnet-ai/agent-framework-incident-triage/

  • Microsoft Agent Framework AIAgent + AgentSession
  • IChatClient provider boundary
  • three read-only function tools
  • deterministic embedded JSON evidence
  • separate runbook guidance
  • evidence IDs and missing-field handling
  • correlation-vs-causation example
  • Evidence-First Agent Contract
  • AI Agent Tool Risk Ladder
  • architecture, verified environment, and captured sample-run docs
  • 14 deterministic tests

• Root README

  • new sample row
  • run commands
  • updated repository structure

• GitHub Actions

  • new test-agent-framework-incident-triage job
  • sample path added to push and pull-request filters
  • no live AI provider key or LLM call in CI

Deliberately omitted

• MCP
• RAG and vector search
• persistent long-term memory
• multi-agent workflows
• automatic remediation
• write-capable operational tools
• human approval workflows
• durable orchestration
• production hosting
• A2A
• AG-UI

Versions

• Target framework: net10.0
• SDK baseline: 10.0.401
• Microsoft.Agents.AI.OpenAI: 1.22.0
• xUnit: 2.9.3

Validation

• dotnet restore — passed
• Release dotnet build — passed
• Release dotnet test — passed (14/14)
• safe no-key application execution — passed
• targeted credential/path scan — clean
• generated build artifacts removed before commit

Important boundary

The Evidence-First Agent Contract and AI Agent Tool Risk Ladder are
application-level reference patterns created for this educational sample.
They are not official Microsoft Agent Framework specifications.