edit book.proto & pom.xml

src/main/proto/book.proto

 syntax = "proto3";
-
 option java_multiple_files = true;
-option java_package = "org.example";
+option java_package = "org.ds.proto";
+
+// enum جديد
+enum BookType {
+  UNKNOWN = 0;
+  FICTION = 1;
+  SCIENCE = 2;
+  TECHNICAL = 3;
+}
 
+// رسالة متداخلة (Nested Message)
+message Author {
+  string name = 1;
+  string country = 2;
+}
+
+// الرسالة الرئيسية
 message Book {
   string title = 1;
-  string author = 2;
-  int32 year = 3;
-  string isbn = 4;
+  Author author = 2;                    // nested message
+  string isbn = 3;
+  int32 year = 4;
+  BookType type = 5;                    // enum
+  repeated string categories = 6;       // repeated field
+  bool available = 7;
+}
+
+// مجموعة كتب
+message Library {
+  repeated Book books = 1;
 }
\ No newline at end of file