Dispatch router silently skips explicit /fs-code when open PR mentions the issue

[durandom]

Problem

When a user comments /fs-code on an issue, the dispatch router's dedup guard silently skips the code agent if any open (non-bot-authored) PR mentions the issue number in its title or body. The skip is only visible as a ##[notice] in the Route job's GitHub Actions logs:

##[notice]Open PR(s) mentioning issue #2774 found — skipping code dispatch

From the issue's perspective, nothing happens — no reaction, no comment, no feedback. The user has no way to know why their explicit command was ignored without digging into Actions logs.

Real-world example

• Issue: [fullsend] E2E: orchestrator — login fallback misses OIDC auto-redirect rhdh-plugin-export-overlays#2774
• Comment: /fs-code by @subhashkhileri (comment)
• Blocking PR: #2776 (authored by the same user, references #2774)
• Workflow run: 29572300262 — Route succeeded, Code stage skipped

The user also tried /fs-fix, which silently did nothing because /fs-fix only routes on PRs (ISSUE_IS_PR == "true"), not issues.

Suggestion

For explicit slash commands (not auto-triggers), post a short comment explaining why the dispatch was skipped. For example:

Skipping /fs-code: open PR #2776 already references this issue. Close or merge the PR to re-enable, or use /fs-code --force to override.

Silent skips are reasonable for auto-triggers (label events, PR opens) where noise should be minimized. But an explicit /fs-code is a deliberate user action — swallowing it silently violates least surprise.

Affected guard checks

1. Code agent dedup: "Open PR(s) mentioning issue found — skipping code dispatch"
2. Fix agent on issues: /fs-fix silently doesn't match because ISSUE_IS_PR == "false" — no feedback that fix only works on PRs