ci-required-drift: also skip jobs gated on github.ref (fixes mc#958/mc#959)

canvas-deploy-reminder has:
  if: needs.changes.outputs.canvas == 'true'
      && github.event_name == 'push'
      && github.ref == 'refs/heads/main'

ci_job_names() only skipped jobs with `github.event_name` in their `if:`.
The `github.ref` branch was invisible to the detector, so
canvas-deploy-reminder was flagged as missing from all-required.needs —
a false positive that fires on every PR touching canvas/ code.

Now the skip check also fires when `github.ref` is present in the `if:`
condition string, matching the same rationale as the event_name skip:
these jobs never execute in a PR context, so requiring them under
all-required.needs: is not meaningful.

Refs: mc#958 (main), mc#959 (staging)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.gitea/scripts/ci-required-drift.py

@@ -203,12 +203,17 @@ def ci_jobs_all(ci_doc: dict) -> set[str]:
 
 def ci_job_names(ci_doc: dict) -> set[str]:
     """Set of job keys in ci.yml MINUS the sentinel itself MINUS jobs
-    whose `if:` gates on `github.event_name` (those are event-scoped
-    and can legitimately be `skipped` for a given trigger; if we
-    required them under the sentinel `needs:`, every PR-only job
+    whose `if:` gates on `github.event_name` or `github.ref` (those are
+    event-scoped and can legitimately be `skipped` for a given trigger;
+    if we required them under the sentinel `needs:`, every PR-only job
     would be `skipped` on push and the sentinel would interpret
     `skipped != success` as failure). RFC §4 spec.
 
+    `github.ref` is the companion gate for jobs that run only on direct
+    pushes to specific branches (e.g. `github.ref == 'refs/heads/main'`).
+    These never execute in a PR context, so flagging them as missing
+    from `all-required.needs:` is a false positive (mc#958 / mc#959).
+
     Used for F1 (jobs missing from sentinel needs). NOT used for F1b
     (typos in needs) — see `ci_jobs_all` for that."""
     jobs = ci_doc.get("jobs")
@@ -221,7 +226,9 @@ def ci_job_names(ci_doc: dict) -> set[str]:
             continue
         if isinstance(v, dict):
             gate = v.get("if")
-            if isinstance(gate, str) and "github.event_name" in gate:
+            if isinstance(gate, str) and (
+                "github.event_name" in gate or "github.ref" in gate
+            ):
                 continue
         names.add(k)
     return names