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/goal/GoalEditorState.dart

@@ -282,7 +282,7 @@ class GoalEditorState extends State<GoalEditor> implements ConnectGoalEditor {
     return Container(
       padding: const EdgeInsets.all(18),
       decoration: BoxDecoration(
-        borderRadius: BorderRadius.circular(20),
+        borderRadius: BorderRadius.zero,
         gradient: LinearGradient(
           begin: Alignment.topLeft,
           end: Alignment.bottomRight,
@@ -338,7 +338,6 @@ class GoalEditorState extends State<GoalEditor> implements ConnectGoalEditor {
             alignment: Alignment.center,
             decoration: BoxDecoration(
               color: colour,
-              shape: BoxShape.circle,
               border: Border.all(
                 color: selected ? colorWhite : Colors.transparent,
                 width: 3,