feat(customization): font switcher with Unbounded, styled via m3e

lib/frontend/screens/profile/customization_screen.dart

@@ -0,0 +1,171 @@
+import 'package:flutter/material.dart';
+import 'package:m3e_collection/m3e_collection.dart';
+import 'package:material_symbols_icons/symbols.dart';
+
+import '../../../core/config/app_fonts.dart';
+import '../../../core/utils/haptics.dart';
+import '../../../main.dart';
+
+class CustomizationScreen extends StatefulWidget {
+  const CustomizationScreen({super.key});
+
+  @override
+  State<CustomizationScreen> createState() => _CustomizationScreenState();
+}
+
+class _CustomizationScreenState extends State<CustomizationScreen> {
+  void _selectFont(String id) {
+    final app = KometApp.stateOf(context);
+    if (app == null || app.fontId == id) return;
+    Haptics.selection();
+    app.applyAppFont(id);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final cs = Theme.of(context).colorScheme;
+    final currentId = KometApp.stateOf(context)?.fontId ?? AppFonts.fallback.id;
+
+    return Scaffold(
+      backgroundColor: cs.surface,
+      appBar: AppBarM3E(
+        titleText: 'Кастомизация',
+        backgroundColor: cs.surface,
+      ),
+      body: SafeArea(
+        top: false,
+        child: ListView(
+          physics: const BouncingScrollPhysics(),
+          padding: const EdgeInsets.fromLTRB(16, 8, 16, 120),
+          children: [
+            _PreviewCard(fontId: currentId),
+            const SizedBox(height: 28),
+            const _SectionLabel(icon: Symbols.text_fields, text: 'Шрифт'),
+            const SizedBox(height: 14),
+            for (final font in AppFonts.all) ...[
+              _FontOption(
+                font: font,
+                selected: font.id == currentId,
+                onTap: () => _selectFont(font.id),
+              ),
+              if (font != AppFonts.all.last) const SizedBox(height: 12),
+            ],
+          ],
+        ),
+      ),
+    );
+  }
+}
+
+class _PreviewCard extends StatelessWidget {
+  final String fontId;
+
+  const _PreviewCard({required this.fontId});
+
+  @override
+  Widget build(BuildContext context) {
+    final cs = Theme.of(context).colorScheme;
+    return Container(
+      width: double.infinity,
+      padding: const EdgeInsets.all(24),
+      decoration: BoxDecoration(
+        color: cs.surfaceContainerHigh,
+        borderRadius: BorderRadius.circular(28),
+      ),
+      child: Column(
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: [
+          Text(
+            'ПРЕДПРОСМОТР',
+            style: TextStyle(
+              color: cs.primary,
+              fontSize: 12,
+              fontWeight: FontWeight.w700,
+              letterSpacing: 1.2,
+            ),
+          ),
+          const SizedBox(height: 16),
+          Text(
+            'Съешь ещё этих мягких булок',
+            style: AppFonts.sample(fontId, fontSize: 22).copyWith(
+              color: cs.onSurface,
+              fontWeight: FontWeight.w600,
+              height: 1.25,
+            ),
+          ),
+          const SizedBox(height: 10),
+          Text(
+            'The quick brown fox 0123',
+            style: AppFonts.sample(fontId, fontSize: 15).copyWith(
+              color: cs.onSurfaceVariant,
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+}
+
+class _SectionLabel extends StatelessWidget {
+  final IconData icon;
+  final String text;
+
+  const _SectionLabel({required this.icon, required this.text});
+
+  @override
+  Widget build(BuildContext context) {
+    final cs = Theme.of(context).colorScheme;
+    return Padding(
+      padding: const EdgeInsets.only(left: 6),
+      child: Row(
+        children: [
+          Icon(icon, size: 20, color: cs.onSurfaceVariant, weight: 500),
+          const SizedBox(width: 8),
+          Text(
+            text,
+            style: TextStyle(
+              color: cs.onSurfaceVariant,
+              fontSize: 15,
+              fontWeight: FontWeight.w700,
+              letterSpacing: 0.3,
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+}
+
+class _FontOption extends StatelessWidget {
+  final AppFont font;
+  final bool selected;
+  final VoidCallback onTap;
+
+  const _FontOption({
+    required this.font,
+    required this.selected,
+    required this.onTap,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return SizedBox(
+      width: double.infinity,
+      child: ButtonM3E(
+        onPressed: onTap,
+        style: selected ? ButtonM3EStyle.filled : ButtonM3EStyle.tonal,
+        size: ButtonM3ESize.xl,
+        shape: ButtonM3EShape.round,
+        selected: selected,
+        icon: Icon(
+          selected ? Symbols.check_circle : Symbols.font_download,
+          fill: selected ? 1 : 0,
+        ),
+        label: Text(
+          font.label,
+          style: AppFonts.sample(font.id, fontSize: 18),
+        ),
+      ),
+    );
+  }
+}

lib/frontend/screens/profile/settings_tab.dart

@@ -9,6 +9,7 @@ import '../../../core/utils/haptics.dart';
 import '../../../l10n/app_localizations.dart';
 import '../../../main.dart';
 import '../auth/proxy_settings_sheet.dart';
+import 'customization_screen.dart';
 import 'debug_menu_screen.dart';
 import 'devices_screen.dart';
 import 'edit_profile_screen.dart';
@@ -142,6 +143,29 @@ child: _buildSection(
                 ),
               ),
             ),
+            SliverToBoxAdapter(
+              child: Padding(
+                padding: const EdgeInsets.fromLTRB(16, 12, 16, 0),
+                child: _buildSection(
+                  context,
+                  cs,
+                  items: [
+                    _SettingsItem(
+                      icon: Symbols.palette,
+                      label: 'Кастомизация',
+                      onTap: () {
+                        Navigator.push(
+                          context,
+                          MaterialPageRoute(
+                            builder: (context) => const CustomizationScreen(),
+                          ),
+                        );
+                      },
+                    ),
+                  ],
+                ),
+              ),
+            ),
             SliverToBoxAdapter(
               child: Padding(
                 padding: const EdgeInsets.fromLTRB(16, 12, 16, 0),