feat: Add forms showcase screen and routing

This commit introduces a new "Forms" component showcase screen to the application, providing a dedicated area to demonstrate form-related UI elements.

### Key Changes:

*   **New Screen (`lib/screens/components/forms/forms_screen.dart`):**
    *   Created `FormsScreen` to display form component examples.
    *   Added a `CodeCard` demonstration for `PrimaryButton` variants (standard, with leading/trailing icons, and disabled states) including relevant code snippets.

*   **Routing and Navigation:**
    *   **`lib/routes/route_names.dart`:** Added `forms` and `formsUrl` constants.
    *   **`lib/routes/route_config.dart`:** Integrated `FormsScreen` into the GoRouter configuration as a new `StatefulShellBranch`.
    *   **`lib/settings/navigation_items.dart`:** Added a "Forms" navigation item with the `LucideIcons.filePenLine` icon to the sidebar/navigation menu.

Author: vmeng-b

lib/routes/route_config.dart

@@ -6,6 +6,7 @@ import 'package:police_flutter_template/screens/auth/auth_not_initialized_screen
 import 'package:police_flutter_template/screens/components/alerts/alerts_screen.dart';
 import 'package:police_flutter_template/screens/components/buttons/buttons_screen.dart';
 import 'package:police_flutter_template/screens/components/cards/cards_screen.dart';
+import 'package:police_flutter_template/screens/components/forms/forms_screen.dart';
 import 'package:police_flutter_template/screens/components/lists/lists_screen.dart';
 import 'package:police_flutter_template/screens/error_pages/internal_server_error_screen.dart';
 import 'package:police_flutter_template/screens/error_pages/not_found_screen.dart';
@@ -205,6 +206,15 @@ class RouteConfig {
                 ),
               ],
             ),
+            StatefulShellBranch(
+              routes: [
+                GoRoute(
+                  name: RouteNames.forms,
+                  path: RouteNames.formsUrl,
+                  builder: (context, state) => FormsScreen(),
+                ),
+              ],
+            ),
           ],
         ),
       ],

lib/routes/route_names.dart

@@ -64,4 +64,10 @@ class RouteNames {
 
   /// URL path for the lists demo route (e.g. `/lists`).
   static const String listsUrl = '/$lists';
+
+  /// Route name for the "forms" component showcase/demo screen.
+  static const String forms = "forms";
+
+  /// URL path for the forms demo route (e.g. `/forms`).
+  static const String formsUrl = '/$forms';
 }

lib/screens/components/forms/forms_screen.dart

@@ -0,0 +1,80 @@
+import 'package:shadcn_flutter/shadcn_flutter.dart';
+import '../../../extensions/text_extensions.dart';
+import '../../widgets/code_card.dart';
+
+class FormsScreen extends StatelessWidget {
+  const FormsScreen({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return Column(
+      mainAxisSize: MainAxisSize.max,
+      children: [
+        Gap(64),
+        Text('Formular-Elemente').h3.setColors(
+          lightColor: Colors.gray[800],
+          darkColor: Colors.white,
+        ),
+        Gap(50),
+        ConstrainedBox(
+          constraints: BoxConstraints(maxWidth: 1000),
+          child: Column(
+            children: [
+              Row(
+                mainAxisAlignment: MainAxisAlignment.center,
+                children: [
+                  ConstrainedBox(
+                    constraints: BoxConstraints(maxWidth: 900),
+                    child: CodeCard(
+                      title: 'Primäre Buttons',
+                      example: Row(
+                        children: [
+                          PrimaryButton(
+                            onPressed: () {},
+                            child: const Text('Standard'),
+                          ),
+                          Gap(10),
+                          PrimaryButton(
+                            leading: const Icon(LucideIcons.download),
+                            onPressed: () {},
+                            child: const Text('Mit Icon vorne'),
+                          ),
+                          Gap(10),
+                          PrimaryButton(
+                            trailing: const Icon(LucideIcons.arrowRight),
+                            onPressed: () {},
+                            child: const Text('Mit Icon hinten'),
+                          ),
+                          Gap(10),
+                          PrimaryButton(
+                            child: const Text('Deaktiviert'),
+                          ),
+                        ],
+                      ),
+                      lines: [
+                        CodeCommentLine("# Beispiel für Primäre Buttons"),
+                        CodeTextLine("PrimaryButton("),
+                        CodeCommentLine("  # Mit Icon vorne"),
+                        CodeTextLine("  leading: const Icon(LucideIcons.download),"),
+                        CodeCommentLine("  # Mit Icon hinten"),
+                        CodeTextLine("  trailing: const Icon(LucideIcons.arrowRight),"),
+                        CodeCommentLine("  # Für aktiven Button (bei deaktiviertem Button weglassen)"),
+                        CodeTextLine("  onPressed: () {},"),
+                        CodeCommentLine("  # Text des Buttons"),
+                        CodeTextLine("  child: const Text('Primärer Button'),"),
+                        CodeTextLine("),"),
+                      ],
+                    ),
+                  ).withPadding(horizontal: 10),
+                ],
+              ),
+              Gap(20),
+            ],
+          ),
+        ),
+
+        Gap(64),
+      ],
+    );
+  }
+}

lib/settings/navigation_items.dart

@@ -92,6 +92,12 @@ class NavigationItems {
           icon: const Icon(LucideIcons.list),
           onPressed: () => navigationShell.goBranch(4, initialLocation: false),
         ),
+        NavigationItemModel(
+          index: 5,
+          title: "Forms",
+          icon: const Icon(LucideIcons.filePenLine),
+          onPressed: () => navigationShell.goBranch(5, initialLocation: false),
+        ),
         NavigationItemModel(
           index: null,
           title: "404 Nicht gefunden - Standalone",