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/ar.json

@@ -412,7 +412,8 @@
       "leave": "الإجازة",
       "payroll": "الرواتب",
       "access": "صلاحيات الفروع",
-      "credentials": "بيانات الدخول"
+      "credentials": "بيانات الدخول",
+      "team": "الموظفون"
     },
     "myAttendance": "حضوري",
     "clockIn": "تسجيل دخول",
@@ -437,6 +438,33 @@
       "saved": "تم حفظ بيانات الدخول.",
       "removed": "تم حذف بيانات الدخول.",
       "usernameTaken": "اسم المستخدم هذا مستخدم بالفعل."
+    },
+    "addEmployee": "إضافة موظف",
+    "noEmployees": "لا يوجد موظفون بعد.",
+    "employeeCreated": "تمت إضافة الموظف",
+    "save": "حفظ",
+    "cancel": "إلغاء",
+    "fields": {
+      "name": "الاسم",
+      "phone": "الجوال",
+      "role": "الدور",
+      "branch": "الفرع",
+      "branchOptional": "اختياري",
+      "noBranch": "بدون فرع",
+      "baseSalary": "الراتب الأساسي (تومان)",
+      "optional": "اختياري",
+      "enableLogin": "إنشاء اسم مستخدم وكلمة مرور",
+      "username": "اسم المستخدم",
+      "password": "كلمة المرور",
+      "passwordHint": "8 أحرف على الأقل"
+    },
+    "roles": {
+      "Owner": "المالك",
+      "Manager": "مدير",
+      "Cashier": "أمين الصندوق",
+      "Waiter": "نادل",
+      "Chef": "طاهٍ",
+      "Delivery": "موصّل"
     }
   },
   "reviews": {