Add contribution payment options to registries

- Added support for single and amount-specific QR codes.
- Updated `RegistrySettings` model and database schema.
- Enhanced `RegistryAdmin` to configure payment options.
- Introduced `RegistryContributionAmount` for partial fulfillment.
- Updated `RegistryPublic` to display contribution progress.
- Added new models for payment methods and QR code handling.
- Improved privacy by limiting contributor visibility.

src/BirthList.Web/Features/Registries/RegistryService.cs

@@ -4,6 +4,7 @@ using BirthList.Web.Data;
 using Microsoft.EntityFrameworkCore;
 using System.Security.Cryptography;
 using System.Text;
+using System.Text.Json;
 
 namespace BirthList.Web.Features.Registries;
 
@@ -210,6 +211,8 @@ internal sealed class RegistryService(RegistryDbContext registryDbContext, Appli
             BankAccountBic = settings?.BankAccountBic,
             BankAccountDisplayName = settings?.BankAccountDisplayName,
             ShowBankAccountName = settings?.ShowBankAccountName ?? false,
+            ContributionQrCodeUrl = settings?.ContributionQrCodeUrl,
+            ContributionAmountQrCodes = ParseContributionAmountQrCodes(settings?.ContributionAmountQrCodesJson),
             CurrentUserId = userId,
             IsAdmin = isAdmin,
             Items = registry.Items
@@ -289,7 +292,9 @@ internal sealed class RegistryService(RegistryDbContext registryDbContext, Appli
             BankAccountIban = settings?.BankAccountIban,
             BankAccountBic = settings?.BankAccountBic,
             BankAccountDisplayName = settings?.BankAccountDisplayName,
-            ShowBankAccountName = settings?.ShowBankAccountName ?? false
+            ShowBankAccountName = settings?.ShowBankAccountName ?? false,
+            ContributionQrCodeUrl = settings?.ContributionQrCodeUrl,
+            ContributionAmountQrCodes = ParseContributionAmountQrCodes(settings?.ContributionAmountQrCodesJson).ToList()
         };
     }
 
@@ -325,10 +330,68 @@ internal sealed class RegistryService(RegistryDbContext registryDbContext, Appli
         settings.BankAccountBic = string.IsNullOrWhiteSpace(model.BankAccountBic) ? null : model.BankAccountBic.Trim();
         settings.BankAccountDisplayName = string.IsNullOrWhiteSpace(model.BankAccountDisplayName) ? null : model.BankAccountDisplayName.Trim();
         settings.ShowBankAccountName = model.ShowBankAccountName;
+        settings.ContributionQrCodeUrl = string.IsNullOrWhiteSpace(model.ContributionQrCodeUrl) ? null : model.ContributionQrCodeUrl.Trim();
+        settings.ContributionAmountQrCodesJson = SerializeContributionAmountQrCodes(model.ContributionAmountQrCodes);
 
         await registryDbContext.SaveChangesAsync(cancellationToken).ConfigureAwait(false);
     }
 
+    private static IReadOnlyList<ContributionAmountQrCodeModel> ParseContributionAmountQrCodes(string? json)
+    {
+        if (string.IsNullOrWhiteSpace(json))
+        {
+            return [];
+        }
+
+        try
+        {
+            var items = JsonSerializer.Deserialize<List<ContributionAmountQrCodeModel>>(json);
+            if (items is null)
+            {
+                return [];
+            }
+
+            return items
+                .Where(x => x.Amount > 0 && !string.IsNullOrWhiteSpace(x.QrCodeUrl))
+                .Select(x => new ContributionAmountQrCodeModel
+                {
+                    Amount = x.Amount,
+                    QrCodeUrl = x.QrCodeUrl.Trim()
+                })
+                .OrderBy(x => x.Amount)
+                .ToList();
+        }
+        catch (JsonException)
+        {
+            return [];
+        }
+    }
+
+    private static string? SerializeContributionAmountQrCodes(IEnumerable<ContributionAmountQrCodeModel>? amountQrCodes)
+    {
+        if (amountQrCodes is null)
+        {
+            return null;
+        }
+
+        var normalized = amountQrCodes
+            .Where(x => x.Amount > 0 && !string.IsNullOrWhiteSpace(x.QrCodeUrl))
+            .Select(x => new ContributionAmountQrCodeModel
+            {
+                Amount = x.Amount,
+                QrCodeUrl = x.QrCodeUrl.Trim()
+            })
+            .OrderBy(x => x.Amount)
+            .ToList();
+
+        if (normalized.Count == 0)
+        {
+            return null;
+        }
+
+        return JsonSerializer.Serialize(normalized);
+    }
+
     public async Task<IReadOnlyList<RegistryItemEditModel>> GetRegistryItemsAsync(Guid registryId, CancellationToken cancellationToken)
     {
         var items = await registryDbContext.RegistryItems