Add optional KYC flow and service-backed account limits

frontend/app/lib/kyc/photo.dart

@@ -0,0 +1,78 @@
+import 'package:flutter/material.dart';
+
+import 'package:sxchnge_kyc/sxchnge_kyc.dart';
+
+import 'preview.dart';
+
+import '../generated/i18n/app_localizations.dart';
+
+class PhotoPanel extends StatelessWidget {
+  const PhotoPanel({
+    super.key,
+    required this.kind,
+    required this.photo,
+    this.onPick,
+    this.onRemove,
+    this.review = false,
+  });
+  final PhotoKind kind;
+  final Photo? photo;
+  final VoidCallback? onPick;
+  final VoidCallback? onRemove;
+  final bool review;
+  @override
+  Widget build(BuildContext context) {
+    final l = AppLocalizations.of(context)!;
+    final t = Theme.of(context);
+    final passport = kind == PhotoKind.passport;
+    final title = passport ? l.kycPassport : l.kycSelfie;
+    return Card(
+      child: Padding(
+        padding: const EdgeInsets.all(20),
+        child: Column(
+          crossAxisAlignment: CrossAxisAlignment.stretch,
+          children: [
+            Text(title, style: t.textTheme.titleLarge),
+            const SizedBox(height: 16),
+            if (photo != null)
+              ClipRRect(
+                borderRadius: BorderRadius.circular(16),
+                child: PhotoPreview(photo: photo!, label: title),
+              )
+            else
+              Container(
+                height: 140,
+                decoration: BoxDecoration(
+                  color: t.colorScheme.surfaceContainerHighest,
+                  borderRadius: BorderRadius.circular(16),
+                ),
+                child: Icon(
+                  passport ? Icons.badge_outlined : Icons.portrait_outlined,
+                  size: 64,
+                  color: t.colorScheme.primary,
+                ),
+              ),
+            if (!review) ...[
+              const SizedBox(height: 16),
+              Text(passport ? l.kycPassportHelp : l.kycSelfieHelp),
+              const SizedBox(height: 12),
+              Text(l.kycFileRules, style: t.textTheme.bodySmall),
+              const SizedBox(height: 16),
+              OutlinedButton.icon(
+                key: ValueKey('pick-${kind.name}'),
+                onPressed: onPick,
+                icon: const Icon(Icons.add_photo_alternate_outlined),
+                label: Text(
+                  photo == null ? l.kycChoose : l.kycReplace,
+                  textAlign: TextAlign.center,
+                ),
+              ),
+              if (photo != null)
+                TextButton(onPressed: onRemove, child: Text(l.kycRemove)),
+            ],
+          ],
+        ),
+      ),
+    );
+  }
+}