test(behaviour): add triage dispatch trigger scenarios (bash routing)

[ifireball]

What is missing

Behaviour tests cover triage dispatch triggers partially, but triage has no behaviour scenarios that verify dispatch triggers fire the correct agent run on the current bash router in reusable-dispatch.yml.

We need this baseline before porting triage's trigger logic to harness CEL expressions.

What should happen

One vertical PR adds Godog scenarios for triage dispatch triggers:

• Triggers: ready-for-triage label, /fs-triage, needs-info re-triage
• Uses bash route job only (no CEL, no harness-dispatch)
• Agent runs via dummy runtime; assert outcome (e.g. behaviour-results.json or expected side effect)
• Requires behaviour framework (PR #1982)

Merge criterion

make behaviour-test green with new triage trigger scenarios.

Blocks

Port triage to harness CEL trigger (#2896).

Related

Part of epic #2888. Does not block the custom-agent harness-dispatch issue (#2889).

[fullsend-ai-triage]

🤖 Triage · ⚠️ Cancelled · Started 8:33 AM UTC · Ended 8:34 AM UTC
Commit: 9f4f2b6 · View workflow run →

[fullsend-ai-triage]

🤖 Finished Triage · ✅ Success · Started 8:35 AM UTC · Completed 8:37 AM UTC
Commit: 9f4f2b6 · View workflow run →