Square every corner, enlarge the main surfaces and add a to-do list

Rounded rectangles and round controls are now square across the app; only
status dots, glows, the sun, rings and the breathing circle stay round.
Cards, rows, thumbnails, featured cards, category tiles, the standing card
and the nav are larger. Home gets a quick To-do list kept on the device
(TodoItem in InternalMemory), seeded with sample items in mock mode.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KhQh614DMeYoQEH9SoMRUw

frontend/lib/Grounded/see/excuse/ExcuseReportState.dart

@@ -142,7 +142,7 @@ class ExcuseReportState extends State<ExcuseReport>
                 padding: const EdgeInsets.all(14),
                 decoration: BoxDecoration(
                   color: colorInset,
-                  borderRadius: BorderRadius.circular(12),
+                  borderRadius: BorderRadius.zero,
                   border: Border.all(color: colorBorder, width: 1),
                 ),
                 child: Row(