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/reportcard/ReportCardScreenState.dart

@@ -99,7 +99,7 @@ class ReportCardScreenState extends State<ReportCardScreen>
       padding: const EdgeInsets.fromLTRB(16, 14, 16, 14),
       decoration: BoxDecoration(
         color: colorWhite.withValues(alpha: 0.08),
-        borderRadius: BorderRadius.circular(16),
+        borderRadius: BorderRadius.zero,
       ),
       child: Row(
         children: [
@@ -128,7 +128,7 @@ class ReportCardScreenState extends State<ReportCardScreen>
               alignment: Alignment.center,
               decoration: BoxDecoration(
                 color: colorWhite,
-                borderRadius: BorderRadius.circular(16),
+                borderRadius: BorderRadius.zero,
               ),
               child: text(_report.grade, 26, TextType.Light,
                   color: colorPrimaryDark),