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/designs/input/CountStepper.dart

@@ -17,7 +17,7 @@ Widget countStepper(
     padding: const EdgeInsets.fromLTRB(14, 10, 8, 10),
     decoration: BoxDecoration(
       color: colorWhite,
-      borderRadius: BorderRadius.circular(12),
+      borderRadius: BorderRadius.zero,
       border: Border.all(color: colorBorder, width: 1),
     ),
     child: Row(
@@ -54,7 +54,7 @@ Widget _stepButton(IconData icon, VoidCallback? onTap) {
       alignment: Alignment.center,
       decoration: BoxDecoration(
         color: enabled ? colorSecondary : colorInset,
-        borderRadius: BorderRadius.circular(10),
+        borderRadius: BorderRadius.zero,
       ),
       child: Icon(icon,
           size: 14, color: enabled ? colorPrimaryDark : colorGrey),

frontend/lib/Grounded/designs/input/InputFields.dart

@@ -54,19 +54,19 @@ Widget inputField(
           contentPadding:
               const EdgeInsets.symmetric(horizontal: 14, vertical: 14),
           enabledBorder: OutlineInputBorder(
-            borderRadius: BorderRadius.circular(12),
+            borderRadius: BorderRadius.zero,
             borderSide: BorderSide(color: colorBorder, width: 1),
           ),
           focusedBorder: OutlineInputBorder(
-            borderRadius: BorderRadius.circular(12),
+            borderRadius: BorderRadius.zero,
             borderSide: BorderSide(color: colorPrimaryDark, width: 1.4),
           ),
           errorBorder: OutlineInputBorder(
-            borderRadius: BorderRadius.circular(12),
+            borderRadius: BorderRadius.zero,
             borderSide: BorderSide(color: colorNegative, width: 1),
           ),
           focusedErrorBorder: OutlineInputBorder(
-            borderRadius: BorderRadius.circular(12),
+            borderRadius: BorderRadius.zero,
             borderSide: BorderSide(color: colorNegative, width: 1.4),
           ),
           errorStyle: TextStyle(
@@ -80,6 +80,36 @@ Widget inputField(
   );
 }
 
+/// The bare add-a-line field used inside a card: no label, no box of its
+/// own; return or the trailing button submits.
+Widget quickAddField(
+  TextEditingController controller,
+  String hint,
+  ValueChanged<String> onSubmitted,
+) {
+  return TextField(
+    controller: controller,
+    onSubmitted: onSubmitted,
+    textInputAction: TextInputAction.done,
+    style: TextStyle(
+      fontFamily: getTextType(TextType.Regular),
+      fontSize: 16,
+      color: colorInk,
+    ),
+    decoration: InputDecoration(
+      hintText: hint,
+      hintStyle: TextStyle(
+        fontFamily: getTextType(TextType.Regular),
+        fontSize: 16,
+        color: colorInkSoft,
+      ),
+      isDense: true,
+      border: InputBorder.none,
+      contentPadding: const EdgeInsets.symmetric(vertical: 14),
+    ),
+  );
+}
+
 /// The excuse field. Deliberately unadorned — no templates, no quick-picks, a
 /// live character count that shows the minimum, because the friction is the
 /// feature rather than an obstacle to route around.
@@ -131,19 +161,19 @@ Widget excuseField(
           fillColor: colorWhite,
           contentPadding: const EdgeInsets.all(14),
           enabledBorder: OutlineInputBorder(
-            borderRadius: BorderRadius.circular(12),
+            borderRadius: BorderRadius.zero,
             borderSide: BorderSide(color: colorBorder, width: 1),
           ),
           focusedBorder: OutlineInputBorder(
-            borderRadius: BorderRadius.circular(12),
+            borderRadius: BorderRadius.zero,
             borderSide: BorderSide(color: colorPrimaryDark, width: 1.4),
           ),
           errorBorder: OutlineInputBorder(
-            borderRadius: BorderRadius.circular(12),
+            borderRadius: BorderRadius.zero,
             borderSide: BorderSide(color: colorNegative, width: 1),
           ),
           focusedErrorBorder: OutlineInputBorder(
-            borderRadius: BorderRadius.circular(12),
+            borderRadius: BorderRadius.zero,
             borderSide: BorderSide(color: colorNegative, width: 1.4),
           ),
           errorStyle: TextStyle(
@@ -180,7 +210,7 @@ Widget selectField(
           padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 16),
           decoration: BoxDecoration(
             color: colorWhite,
-            borderRadius: BorderRadius.circular(12),
+            borderRadius: BorderRadius.zero,
             border: Border.all(color: colorBorder, width: 1),
           ),
           child: Row(