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/splash/SplashState.dart

@@ -239,7 +239,7 @@ class SplashState extends State<Splash> implements ConnectSplash {
           ],
         ),
         GlassSurface(
-          radius: BorderRadius.circular(99),
+          radius: BorderRadius.zero,
           padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 7),
           child: Row(
             mainAxisSize: MainAxisSize.min,
@@ -299,11 +299,11 @@ class SplashState extends State<Splash> implements ConnectSplash {
 
   Widget _mark() {
     return GlassSurface(
-      radius: BorderRadius.circular(46),
+      radius: BorderRadius.zero,
       padding: const EdgeInsets.all(10),
       child: Container(
         decoration: BoxDecoration(
-          borderRadius: BorderRadius.circular(34),
+          borderRadius: BorderRadius.zero,
           boxShadow: <BoxShadow>[
             BoxShadow(
               color: colorPrimary.withValues(alpha: 0.4),
@@ -342,7 +342,7 @@ class SplashState extends State<Splash> implements ConnectSplash {
       alignment: alignment,
       child: Container(
         decoration: BoxDecoration(
-          borderRadius: BorderRadius.circular(99),
+          borderRadius: BorderRadius.zero,
           boxShadow: const [
             BoxShadow(
               color: Color(0x142A3A30),
@@ -352,7 +352,7 @@ class SplashState extends State<Splash> implements ConnectSplash {
           ],
         ),
         child: GlassSurface(
-          radius: BorderRadius.circular(99),
+          radius: BorderRadius.zero,
           tint: colorGlassStrong,
           padding: const EdgeInsets.fromLTRB(4, 4, 12, 4),
           child: Row(
@@ -424,7 +424,7 @@ class SplashState extends State<Splash> implements ConnectSplash {
   /// The whole idea in three beats, on glass over the valley.
   Widget _howItWorks() {
     return GlassSurface(
-      radius: BorderRadius.circular(24),
+      radius: BorderRadius.zero,
       tint: colorGlassStrong,
       padding: const EdgeInsets.fromLTRB(14, 14, 14, 14),
       child: Row(
@@ -499,7 +499,7 @@ class SplashState extends State<Splash> implements ConnectSplash {
     return Column(
       children: [
         GlassSurface(
-          radius: BorderRadius.circular(99),
+          radius: BorderRadius.zero,
           padding: const EdgeInsets.all(3),
           child: SizedBox(
             width: 150,
@@ -510,7 +510,7 @@ class SplashState extends State<Splash> implements ConnectSplash {
                 width: 150,
                 decoration: BoxDecoration(
                   color: colorNight,
-                  borderRadius: BorderRadius.circular(99),
+                  borderRadius: BorderRadius.zero,
                 ),
               ).animate().scaleX(
                     begin: 0.04,