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.

web/dashboard/messages/fa.json

@@ -431,7 +431,8 @@
       "leave": "مرخصی",
       "payroll": "حقوق",
       "access": "دسترسی شعب",
-      "credentials": "رمز ورود"
+      "credentials": "رمز ورود",
+      "team": "کارکنان"
     },
     "myAttendance": "حضور من",
     "clockIn": "ورود",
@@ -456,6 +457,33 @@
       "saved": "رمز ورود ذخیره شد.",
       "removed": "رمز ورود حذف شد.",
       "usernameTaken": "این نام کاربری قبلاً استفاده شده است."
+    },
+    "addEmployee": "افزودن کارمند",
+    "noEmployees": "هنوز کارمندی ثبت نشده است.",
+    "employeeCreated": "کارمند اضافه شد",
+    "save": "ذخیره",
+    "cancel": "انصراف",
+    "fields": {
+      "name": "نام",
+      "phone": "موبایل",
+      "role": "نقش",
+      "branch": "شعبه",
+      "branchOptional": "اختیاری",
+      "noBranch": "بدون شعبه",
+      "baseSalary": "حقوق پایه (تومان)",
+      "optional": "اختیاری",
+      "enableLogin": "ایجاد نام کاربری و رمز ورود",
+      "username": "نام کاربری",
+      "password": "رمز عبور",
+      "passwordHint": "حداقل ۸ کاراکتر"
+    },
+    "roles": {
+      "Owner": "مالک",
+      "Manager": "مدیر",
+      "Cashier": "صندوق‌دار",
+      "Waiter": "گارسون",
+      "Chef": "آشپز",
+      "Delivery": "پیک"
     }
   },
   "reviews": {