Fix spelling of "grey" to "gray" in counter types and documentation

Author: TechAurelian

lib/data/counter_ideas.dart

@@ -281,7 +281,7 @@ const Map<CounterType, List<String>> counterIdeas = {
     'Fires I had to put out at work (metaphorically)',
     'Orange juice glasses consumed with breakfast',
   ],
-  CounterType.grey: [
+  CounterType.gray: [
     // --- VISUAL (Weather, City, Nature) ---
     'Rainy days where I just stayed inside',
     'Pigeons that refused to move out of my way',

lib/models/counter.dart

@@ -9,7 +9,7 @@ import 'package:flutter/material.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
 /// Counter (color) types.
-enum CounterType { black, white, red, green, yellow, blue, brown, purple, pink, orange, grey }
+enum CounterType { black, white, red, green, yellow, blue, brown, purple, pink, orange, gray }
 
 /// An integer counter class.
 class Counter {
@@ -87,7 +87,7 @@ class Counter {
     CounterType.purple: Colors.purple,
     CounterType.pink: Colors.pink,
     CounterType.orange: Colors.orange,
-    CounterType.grey: Colors.grey,
+    CounterType.gray: Colors.grey,
   };
 }
 

lib/widgets/color_list_tile.dart

@@ -29,7 +29,7 @@ class ColorListTile extends StatelessWidget {
   /// The additional text content displayed below the title.
   final String subtitle;
 
-  /// This color list tile is currently selected, and will be rendered with a grey background.
+  /// This color list tile is currently selected, and will be rendered with a gray background.
   final bool selected;
 
   /// Called when the user taps this list tile.