fix(ci): set loop/code label on Firebase test failure issues (#551)

Closes #550

## Summary

When Firebase instrumented tests fail in the nightly run, the workflow opens a tracking issue. It currently tags it with the legacy `Ready` label, which is not part of the current agent loop. Switch the label to `loop/code` so the coding agent picks it up automatically and the error gets fixed.

## Change

- `.forgejo/workflows/firebase-tests.yml`: set `loop/code` instead of `Ready` on the created failure issue.

## Test plan

- [ ] Wait for next scheduled (or manually dispatched) Firebase test failure and confirm the created issue carries the `loop/code` label.

Co-authored-by: guettlibot <tilldu@googlemail.com>
Reviewed-on: https://codeberg.org/guettli/sharedinbox/pulls/551

.forgejo/workflows/firebase-tests.yml

@@ -135,7 +135,7 @@ jobs:
           repo_labels = api_get("/labels")
           label_map = {l["name"]: l["id"] for l in repo_labels}
 
-          label_ids = [label_map["Ready"]] if "Ready" in label_map else []
+          label_ids = [label_map["loop/code"]] if "loop/code" in label_map else []
 
           title = "Firebase Tests failed — find root cause and fix"
           body = (