fix(scheduler): derive rotation offset from wall-clock, not a reset-on-restart counter

The lead-user rotation used an in-memory pass counter reset to 0 on every pod
restart, so the first-listed user always re-took the lead after a restart — a
deploy-heavy session re-starved the last user (the pilot stalled at 2 summaries
because each deploy reset his every-other-pass lead before the 2h tick fired).
Derive the offset from wall-clock (floor(now/interval)) so it advances with real
time and is identical across restarts: rotation stays fair however often the pod
bounces.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

cmd/tapir/scheduler.go

@@ -143,8 +143,18 @@ func runScheduler(
 		return // disabled
 	}
 
-	pass := 0
+	// Derive the rotation offset from wall-clock, NOT an in-memory counter. A
+	// counter reset to 0 on every pod restart always hands the lead to the
+	// first-listed user — so frequent deploys re-starve whoever is last (exactly
+	// what happened to the first pilot user during a deploy-heavy session). A
+	// time-based offset advances with real time and is identical across restarts,
+	// so the lead rotates fairly regardless of how often the pod bounces.
+	runPass := func() {
+		pass := int(time.Now().Unix() / int64(interval/time.Second))
 		runDiscoveryPass(ctx, pass, lister, runUser, log)
+	}
+
+	runPass()
 
 	ticker := time.NewTicker(interval)
 	defer ticker.Stop()
@@ -153,8 +163,7 @@ func runScheduler(
 		case <-ctx.Done():
 			return
 		case <-ticker.C:
-			pass++
-			runDiscoveryPass(ctx, pass, lister, runUser, log)
+			runPass()
 		}
 	}
 }