Captures page: the recording checklist with one start/end button

Steps come from a bundled copy of contracts checklists/ (assets/contracts/,
refreshed by tool/sync-contracts.sh), not from Dart.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DDwfd6Ki8UfG4hK6W5YpJz

lib/main.dart

@@ -7,6 +7,7 @@ import 'package:flutter/material.dart';
 
 import 'boundary.dart';
 import 'camview.dart';
+import 'checklist.dart';
 import 'linktest.dart';
 import 'net.dart';
 
@@ -250,6 +251,15 @@ class LinkBar extends StatelessWidget {
                 icon: const Icon(Icons.videocam),
                 label: const Text('Camera'),
               ),
+              TextButton.icon(
+                onPressed: () => Navigator.of(context).push(
+                  MaterialPageRoute<void>(
+                    builder: (_) => ChecklistsPage(boundary: b),
+                  ),
+                ),
+                icon: const Icon(Icons.checklist),
+                label: const Text('Captures'),
+              ),
             ],
           ),
         ),