Refactor code structure for improved readability and maintainability; optimize performance in key functions.

src/Findings/StellaOps.Findings.Ledger.WebService/Services/FindingSummaryService.cs

@@ -0,0 +1,68 @@
+using StellaOps.Findings.Ledger.WebService.Contracts;
+
+namespace StellaOps.Findings.Ledger.WebService.Services;
+
+public interface IFindingSummaryService
+{
+    Task<FindingSummary?> GetSummaryAsync(Guid findingId, CancellationToken ct);
+    Task<FindingSummaryPage> GetSummariesAsync(FindingSummaryFilter filter, CancellationToken ct);
+}
+
+public sealed class FindingSummaryService : IFindingSummaryService
+{
+    private readonly IFindingSummaryBuilder _builder;
+    private readonly IFindingRepository _repository;
+
+    public FindingSummaryService(
+        IFindingSummaryBuilder builder,
+        IFindingRepository repository)
+    {
+        _builder = builder;
+        _repository = repository;
+    }
+
+    public async Task<FindingSummary?> GetSummaryAsync(Guid findingId, CancellationToken ct)
+    {
+        var finding = await _repository.GetByIdAsync(findingId, ct);
+        if (finding is null)
+            return null;
+
+        return _builder.Build(finding);
+    }
+
+    public async Task<FindingSummaryPage> GetSummariesAsync(FindingSummaryFilter filter, CancellationToken ct)
+    {
+        var (findings, totalCount) = await _repository.GetPagedAsync(
+            page: filter.Page,
+            pageSize: filter.PageSize,
+            status: filter.Status,
+            severity: filter.Severity,
+            minConfidence: filter.MinConfidence,
+            ct);
+
+        var summaries = findings.Select(f => _builder.Build(f)).ToList();
+
+        return new FindingSummaryPage
+        {
+            Items = summaries,
+            TotalCount = totalCount,
+            Page = filter.Page,
+            PageSize = filter.PageSize
+        };
+    }
+}
+
+/// <summary>
+/// Repository for finding data access.
+/// </summary>
+public interface IFindingRepository
+{
+    Task<FindingData?> GetByIdAsync(Guid id, CancellationToken ct);
+    Task<(IReadOnlyList<FindingData> findings, int totalCount)> GetPagedAsync(
+        int page,
+        int pageSize,
+        string? status,
+        string? severity,
+        decimal? minConfidence,
+        CancellationToken ct);
+}