fix(actions): cap dynamic matrix expansion at MaxJobNumPerRun

A matrix built from a dependent job's runtime output (fromJson(needs.*.outputs.*))
has no inherent size bound, so a large or buggy upstream output could insert an
arbitrary number of jobs in one transaction. The per-attempt AttemptJobIDs also
back the job-index URLs, which must stay below MaxJobNumPerRun. Skip the
expansion with a clear reason when the resulting jobs would exceed that limit.

Also rename a test variable that tripped the misspell linter and clarify the
deferred-placeholder commit-status comment.

Co-Authored-By: Claude (Opus 4.8) <noreply@anthropic.com>

services/actions/commit_status.go

@@ -47,7 +47,7 @@ func CreateCommitStatusForRunJobs(ctx context.Context, run *actions_model.Action
 
 	for _, job := range jobs {
 		// A deferred-matrix placeholder's name changes when it expands, so a status created now
-		// would be orphaned; the expanded combos get theirs at expansion time.
+		// would be orphaned; the job emitter creates the combos' statuses after expansion.
 		if job.RawStrategy != "" && !job.IsMatrixEvaluated {
 			continue
 		}