emloyee and user fixings

Backend/ERPCore/Domain/Entities/Employee.cs

@@ -6,8 +6,10 @@ namespace ERPCore.Domain.Entities;
 /// Staff record (FR-HR-MD-02) — distinct from <see cref="User"/> (the system login
 /// account): not every employee has a login, and not every login belongs to an
 /// employee. <see cref="UserId"/> is the optional, explicit, human-confirmed link
-/// between the two (docs/12-BACKEND-HRM.md A.5/C.2, Part B.3.2). Never hard-deleted —
-/// separation is recorded via <see cref="Status"/> + <see cref="LastWorkingDate"/>.
+/// between the two (docs/12-BACKEND-HRM.md A.5/C.2, Part B.3.2). Normal separation is
+/// recorded via <see cref="Status"/> + <see cref="LastWorkingDate"/> rather than deletion;
+/// an explicit hard delete is also available (<see cref="Services.Interfaces.IEmployeeService.DeleteAsync"/>)
+/// and cascades to every dependent HR record, blocked only if payroll history exists.
 /// <see cref="EmployeeCode"/> is user-entered (not <see cref="NumberSequence"/>-issued):
 /// HR departments keep their own legacy numbering scheme, and NumberSequence's
 /// year-scoping is the wrong shape for an identifier that must never look "reset".

Backend/ERPCore/Domain/Entities/LoginActivity.cs

@@ -0,0 +1,22 @@
+namespace ERPCore.Domain.Entities;
+
+/// <summary>
+/// One row per successful sign-in, captured directly by ERPCore (not AuthHex) so an
+/// admin can see a user's device/login history — AuthHex's own session listing only
+/// ever reports the currently-authenticated caller's own sessions, with no admin-scoped
+/// call to inspect anyone else's. This is a history of past logins, not a live "currently
+/// active sessions" view (that would need AuthHex to expose one).
+/// </summary>
+public class LoginActivity
+{
+    public int LoginActivityId { get; set; }
+    public int UserId { get; set; }
+    public User? User { get; set; }
+
+    public string? IpAddress { get; set; }
+    public string? UserAgent { get; set; }
+    /// <summary>Best-effort "Browser on OS" label parsed from <see cref="UserAgent"/> for display.</summary>
+    public string? DeviceLabel { get; set; }
+
+    public DateTime LoginAt { get; set; }
+}

Backend/ERPCore/Domain/Enums/AuditAction.cs

@@ -5,5 +5,8 @@ public enum AuditAction
 {
     Create,
     Update,
-    Delete
+    Delete,
+    /// <summary>A successful sign-in — written explicitly (not via ErpDbContext's automatic
+    /// entity-change capture, since a login mutates nothing) by AuthController.</summary>
+    Login
 }