feat(hr): add employees from the dashboard

Previously the only Employee records were the Owner (created at café signup) and
one Manager per branch — there was no way to add a waiter/cashier/chef. Adds it.

Backend:
- POST /api/cafes/{cafeId}/employees (HrController). Owner/Manager only; creating a
  Manager requires Owner; Owner cannot be created here. Validates name/phone/role,
  enforces one-employee-per-phone, validates branch belongs to the café, and can
  optionally set username/password login in the same step (same hashing + uniqueness
  as the credentials endpoint). Returns EmployeeSummaryDto.

Dashboard:
- New "Team" tab on the HR screen (now the default): employee roster (name, role,
  phone, base salary) + an "Add employee" button (owner/manager) opening an inline
  form — name, phone, role, optional branch, optional base salary, optional login.
- Role labels + all form strings in fa/en/ar.

86 API tests pass; dashboard tsc + build clean.

src/Meezi.API/Models/Hr/HrDtos.cs

@@ -62,3 +62,15 @@ public record TodayShiftDto(ShiftType ShiftType, string Label);
 
 /// <summary>Set or update username/password credentials for an employee.</summary>
 public record SetEmployeeCredentialsRequest(string Username, string Password);
+
+/// <summary>Create a new employee. Owner/Manager only; Manager role requires Owner.
+/// Username+Password are optional and, when supplied, enable dashboard/POS login.</summary>
+public record CreateEmployeeRequest(
+    string Name,
+    string Phone,
+    EmployeeRole Role,
+    string? BranchId = null,
+    decimal? BaseSalary = null,
+    string? NationalId = null,
+    string? Username = null,
+    string? Password = null);