Heartbeat-first dispatch: retire WoL-as-default, add WaitingReboot

Every supported host runs vetting-reporter in-OS and heartbeats every
30s. WoL was never the thing that started vetting — the heartbeat
response's reboot_for_vetting command was. Firing WoL first only
crowded the run log with misleading diagnostics when the real failure
mode is "reporter isn't installed."

- StartRun 409s if the host hasn't heartbeated within 60s, pointing
  the operator at /register/quick.sh.
- Dispatcher re-checks LastSeenAt at dispatch time (run may sit in
  Queued long enough for the host to go offline); stale hosts mark
  the run Failed with failed_stage=dispatch instead of looping.
- New StateWaitingReboot + TriggerRebootCommanded capture the actual
  semantics. StateWaitingWoL kept as the hook point for a future
  manual-override button.
- Tile disables the Start button with a quick.sh tooltip when the
  host is offline, matching the server-side 409.

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

internal/orchestrator/statemachine_test.go

@@ -40,6 +40,40 @@ func TestNextForOverride(t *testing.T) {
 	}
 }
 
+// TestTriggerRebootCommanded exercises the new heartbeat-first trigger:
+// Queued → WaitingReboot, and any other current state is an error.
+func TestTriggerRebootCommanded(t *testing.T) {
+	got, err := orchestrator.Next(model.StateQueued, orchestrator.TriggerRebootCommanded)
+	if err != nil {
+		t.Fatalf("Queued + RebootCommanded: %v", err)
+	}
+	if got != model.StateWaitingReboot {
+		t.Fatalf("got %q, want %q", got, model.StateWaitingReboot)
+	}
+	for _, bad := range []model.RunState{
+		model.StateRegistered, model.StateBooting, model.StateInventoryCheck, model.StateCompleted,
+	} {
+		if _, err := orchestrator.Next(bad, orchestrator.TriggerRebootCommanded); err == nil {
+			t.Fatalf("RebootCommanded from %q: expected error", bad)
+		}
+	}
+}
+
+// TestTriggerAgentClaimedFromWaitingReboot: the agent's /claim must
+// advance the run out of WaitingReboot (new happy path) AND out of
+// legacy WaitingWoL, otherwise live boots wouldn't be recognised.
+func TestTriggerAgentClaimedFromWaitingReboot(t *testing.T) {
+	for _, from := range []model.RunState{model.StateWaitingReboot, model.StateWaitingWoL, model.StateBooting} {
+		got, err := orchestrator.Next(from, orchestrator.TriggerAgentClaimed)
+		if err != nil {
+			t.Fatalf("AgentClaimed from %q: %v", from, err)
+		}
+		if got != model.StateInventoryCheck {
+			t.Fatalf("AgentClaimed from %q = %q, want InventoryCheck", from, got)
+		}
+	}
+}
+
 func TestNextStageWalk(t *testing.T) {
 	// Walking StageCompleted from each stage should land on the next
 	// one in the canonical order, and from Reporting onto Completed.