feat: add contact UI helpers and path editor for routing management

- Implemented contactTypeIcon and contactTypeColor functions for better UI representation of contact types.
- Created colorForName and firstCharacterOrEmoji functions to enhance contact display.
- Developed PathEditorSheet widget for managing contact paths with a user-friendly interface.
- Introduced RoutingSheet for managing contact routing modes and displaying path history.
- Added a script for generating proof of concept (PoC) payloads for clipboard contact import validation.

lib/widgets/gif_picker.dart

@@ -180,7 +180,7 @@ class _GifPickerState extends State<GifPicker> {
           const SizedBox(height: 8),
           Text(
             context.l10n.gifPicker_poweredBy,
-            style: TextStyle(fontSize: 11, color: Colors.grey[600]),
+            style: TextStyle(fontSize: 11, color: Theme.of(context).colorScheme.onSurfaceVariant),
           ),
         ],
       ),
@@ -197,11 +197,11 @@ class _GifPickerState extends State<GifPicker> {
         child: Column(
           mainAxisAlignment: MainAxisAlignment.center,
           children: [
-            Icon(Icons.error_outline, size: 64, color: Colors.grey[400]),
+            Icon(Icons.error_outline, size: 64, color: Theme.of(context).colorScheme.onSurfaceVariant),
             const SizedBox(height: 16),
             Text(
               _error!,
-              style: TextStyle(fontSize: 16, color: Colors.grey[600]),
+              style: TextStyle(fontSize: 16, color: Theme.of(context).colorScheme.onSurfaceVariant),
             ),
             const SizedBox(height: 16),
             ElevatedButton.icon(
@@ -219,11 +219,11 @@ class _GifPickerState extends State<GifPicker> {
         child: Column(
           mainAxisAlignment: MainAxisAlignment.center,
           children: [
-            Icon(Icons.search_off, size: 64, color: Colors.grey[400]),
+            Icon(Icons.search_off, size: 64, color: Theme.of(context).colorScheme.onSurfaceVariant),
             const SizedBox(height: 16),
             Text(
               context.l10n.gifPicker_noGifsFound,
-              style: TextStyle(fontSize: 16, color: Colors.grey[600]),
+              style: TextStyle(fontSize: 16, color: Theme.of(context).colorScheme.onSurfaceVariant),
             ),
           ],
         ),