docs: Add a comment about the implementation details and a race condition

fix: Adjust the lint issues
fix: Add the copyright info

Signed-off-by: Pascal Zimmermann <pascal.zimmermann@theiotstudio.com>

models/actions/task.go

@@ -265,6 +265,12 @@ func CreateTaskForRunner(ctx context.Context, runner *ActionRunner) (*ActionTask
 		}
 
 		// Check max-parallel constraint for matrix jobs
+		// Note: This is a best-effort check with a small race window. Multiple runners
+		// could simultaneously check the count before any commits, potentially allowing
+		// the limit to be briefly exceeded (e.g., if limit=2 and count=1, two runners
+		// might both proceed). Perfect enforcement would require row-level locking across
+		// all jobs with the same run_id+job_id, which has a significant performance impact.
+		// The race window is small since jobs are picked and committed quickly.
 		if v.MaxParallel > 0 {
 			runningCount, err := CountRunningJobsByWorkflowAndRun(ctx, v.RunID, v.JobID)
 			if err != nil {

services/actions/task_assignment_test.go

@@ -147,7 +147,6 @@ func TestMaxParallelJobStatusAndCounting(t *testing.T) {
 
 		for _, tc := range testCases {
 			t.Run(tc.name, func(t *testing.T) {
-
 				// Create jobs with the test max-parallel value
 				for i := range 5 {
 					job := &actions_model.ActionRunJob{