first commit

Backend/ERPCore/Common/Models/PagedResult.cs

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+namespace ERPCore.Common.Models;
+
+/// <summary>Pagination envelope metadata returned alongside a page of items.</summary>
+public sealed record PaginationMeta(int Page, int PageSize, int TotalCount)
+{
+    public int TotalPages => PageSize <= 0 ? 0 : (int)Math.Ceiling(TotalCount / (double)PageSize);
+    public bool HasPrevious => Page > 1;
+    public bool HasNext => Page < TotalPages;
+}
+
+/// <summary>A single page of <typeparamref name="T"/> plus its pagination metadata.</summary>
+public sealed class PagedResult<T>
+{
+    public IReadOnlyList<T> Items { get; init; } = Array.Empty<T>();
+    public PaginationMeta Meta { get; init; } = new(1, 0, 0);
+
+    public PagedResult() { }
+
+    public PagedResult(IReadOnlyList<T> items, int page, int pageSize, int totalCount)
+    {
+        Items = items;
+        Meta = new PaginationMeta(page, pageSize, totalCount);
+    }
+}

Backend/ERPCore/Common/Models/Result.cs

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+namespace ERPCore.Common.Models;
+
+/// <summary>
+/// Lightweight success/failure envelope for service-layer results where an
+/// exception would be overkill. Domain errors that must reach the client as
+/// RFC 7807 ProblemDetails should throw a DomainException instead
+/// (see System/Errors).
+/// </summary>
+public readonly struct Result<T>
+{
+    public bool IsSuccess { get; }
+    public T? Value { get; }
+    public string? ErrorCode { get; }
+    public string? ErrorMessage { get; }
+
+    private Result(bool ok, T? value, string? code, string? message)
+    {
+        IsSuccess = ok;
+        Value = value;
+        ErrorCode = code;
+        ErrorMessage = message;
+    }
+
+    public static Result<T> Success(T value) => new(true, value, null, null);
+    public static Result<T> Failure(string code, string message) => new(false, default, code, message);
+}