perf(actions): batch per-row queries in run, job and cancellation paths (#39723)

Several Actions code paths issued one or more queries per listed row.
They now load in batch, with unchanged output.

- API job list: tasks, steps and runners load in batch
- API run list: latest attempts and their trigger users load in batch
- Repository runs page: the jobs of all active runs load in one query
- Cancelling previous runs and replacing concurrency group entries fetch
their jobs in one query

Per call with 50 rows on SQLite, base vs head:

| Path | Queries | Time |
| --- | --- | --- |
| API job list | 254 → 6 | 12.9 → 1.9 ms |
| API run list | 305 → 207 | 11.7 → 6.2 ms |
| Runs page job loading | 100 → 1 | 6.5 → 0.47 ms |
| `CancelPreviousJobs` | 546 → 496 | ~120 ms, per-job writes dominate |

The remaining run list queries come from per-run repository conversion,
which this PR doesn't change.

---------

Co-authored-by: Zettat123 <zettat123@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>

routers/web/repo/actions/actions.go

@@ -543,17 +543,18 @@ func (data *actionRunListData) processActionRuns(ctx *context.Context) bool {
 		return false
 	}
 
+	activeRuns := slices.DeleteFunc(slices.Clone(data.ActionRuns), func(run *actions_model.ActionRun) bool {
+		return !run.Status.In(actions_model.StatusWaiting, actions_model.StatusRunning, actions_model.StatusBlocked)
+	})
+	jobsByRun, err := actions_model.GetLatestAttemptJobsByRuns(ctx, activeRuns)
+	if err != nil {
+		ctx.ServerError("GetLatestAttemptJobsByRuns", err)
+		return false
+	}
+
 	data.RunErrors = make(map[int64]string)
-	for _, run := range data.ActionRuns {
-		if !run.Status.In(actions_model.StatusWaiting, actions_model.StatusRunning, actions_model.StatusBlocked) {
-			continue
-		}
-		jobs, err := actions_model.GetLatestAttemptJobsByRepoAndRunID(ctx, run.RepoID, run.ID)
-		if err != nil {
-			ctx.ServerError("GetRunJobsByRunID", err)
-			return false
-		}
-		for _, job := range jobs {
+	for _, run := range activeRuns {
+		for _, job := range jobsByRun[run.ID] {
 			// A deferred matrix is unresolvable until its needs finish, so the whole per-job block
 			// is skipped: parsing the payload would report a valid workflow as invalid.
 			if job.IsMatrixDeferred || !job.Status.In(actions_model.StatusWaiting, actions_model.StatusBlocked, actions_model.StatusPending) {