Add explicit CI state classification command for gh-aw PR triage

[davidahmann]

Problem
Operators currently infer check states from heterogeneous GitHub outputs, which leads to false-green triage when no checks is interpreted as success.

Why now
Cross-repo automation is now blocked on a deterministic check-state contract (failed, pending, no checks, policy-blocked).

Current behavior is insufficient
gh pr checks output is human-oriented and inconsistent across repos/workflow setups, so downstream tooling has to guess state.

Expected behavior
Provide a machine-readable classifier command in gh-aw that maps PR check rollups to normalized states.

Acceptance criteria

• Command accepts repo + PR input and emits JSON.
• JSON contains one normalized state plus supporting raw signals.
• no checks reported is explicitly classified as no checks configured/not triggered.
• Policy/account gates are classified separately from product failures.

Validation

• Add fixture-based tests for failed, pending, no checks, and policy-blocked.
• Verify deterministic output shape in CI.

Codepaths

• cmd/gh-aw
• internal/github
• scripts

[pelikhan]

Could you explain more?

[pelikhan]

Is this a new command to gh aw?

[pelikhan]

@github/next-copilot-reviewers

• implement as a new command "checks" in .go
• provide text based and json content using --json
• use helper to add arguments
• add integration test in ci.yml