feat: Add StaffAttire GraphQL schema defining an AttireVerificationStatus enum and StaffAttire type with verification detail

backend/dataconnect/schema/staffAttire.gql

@@ -0,0 +1,21 @@
+enum AttireVerificationStatus {
+  PENDING
+  FAILED
+  SUCCESS
+}
+
+type StaffAttire @table(name: "staff_attires", key: ["staffId", "attireOptionId"]) {
+  staffId: UUID!
+  staff: Staff! @ref(fields: "staffId", references: "id")
+
+  attireOptionId: UUID!
+  attireOption: AttireOption! @ref(fields: "attireOptionId", references: "id")
+
+  # Verification Metadata
+  verificationStatus: AttireVerificationStatus @default(expr: "PENDING")
+  verifiedAt: Timestamp
+  verificationPhotoUrl: String # Proof of ownership
+  
+  createdAt: Timestamp @default(expr: "request.time")
+  updatedAt: Timestamp @default(expr: "request.time")
+}