feat(dispatch): port fix to harness CEL trigger

[ifireball]

What is missing

fix routing logic lives in bash in reusable-dispatch.yml. It is not expressed as a CEL trigger: on the harness file, so routing cannot be customized without editing shared dispatch bash.

What should happen

One vertical PR ports fix only:

Harness

• Add trigger: CEL expressing today's bash routing for: changes_requested, /fs-fix, fork gate
• CEL lint/type-check in the same PR

Gating

• Decide fix-specific gates (may differ from GCD): what moves into fullsend dispatch, what stays in workflow, whether new ADR or harness format extension is needed
• Decide whether roles: config check still applies for fix in a custom-agents world

Workflow

• harness-dispatch handles fix when CEL matches
• Bash route still runs in parallel for shadow/diff until cutover epic child
• Do not remove bash routing for fix in this PR

Tests (same PR)

• Extend behaviour scenarios from test(behaviour): add fix dispatch trigger scenarios (bash routing) #2893 to cover harness-dispatch path
• Unit parity golden: normative fixtures for fix events match bash routing

Prerequisites

• feat(dispatch): add harness-dispatch job with ADR 54 auth, kill switch, and custom-agent behaviour test #2889 (harness-dispatch + custom agent)
• test(behaviour): add fix dispatch trigger scenarios (bash routing) #2893 (fix bash trigger behaviour baseline)

Merge criterion

fix behaviour scenarios green on harness-dispatch; shadow diff shows parity with bash for its trigger set.

Related

Part of epic #2888

[fullsend-ai-triage]

🤖 Finished Triage · ✅ Success · Started 8:34 AM UTC · Completed 8:37 AM UTC
Commit: 9f4f2b6 · View workflow run →

[fullsend-ai-triage]

Triage Summary

This issue is well-specified — it ports the fix agent routing from bash in reusable-dispatch.yml to a CEL trigger: expression on the harness file, as part of the broader CEL dispatch epic (#2888).

However, both declared prerequisites are still open with no associated PRs in flight:

• feat(dispatch): add harness-dispatch job with ADR 54 auth, kill switch, and custom-agent behaviour test #2889 — harness-dispatch job with ADR 54 auth, kill switch, and custom-agent behaviour test (provides the harness-dispatch infrastructure this issue builds on)
• test(behaviour): add fix dispatch trigger scenarios (bash routing) #2893 — fix dispatch trigger behaviour scenarios for bash routing (provides the baseline test fixtures this issue extends)

Work on this issue cannot meaningfully begin until both prerequisites merge. Marking as blocked.

Scope clarity: The issue body provides clear acceptance criteria across harness, gating, workflow, and test dimensions. Once unblocked, this should be ready to code without further clarification.

Blocked by:

• feat(dispatch): add harness-dispatch job with ADR 54 auth, kill switch, and custom-agent behaviour test #2889
• test(behaviour): add fix dispatch trigger scenarios (bash routing) #2893

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Labels: Issue is blocked on open prerequisites #2889 and #2893; adding blocked label and priority/medium to match feature work within the CEL dispatch epic.