Restore original book lists after RTL/LTR linter test cases

Revert test entries in free-programming-books-en.md and free-programming-books-ar.md, restoring the original book lists. This commit removes temporary test data used for validating the RTL/LTR Markdown linter, preparing the repository for merging the PR with a clean state.

No functional changes to the linter or configuration files; only test content has been removed.

Author: gabriele-ciccotelli

books/free-programming-books-ar.md

@@ -41,13 +41,11 @@
 
 * [التحريك عبر CSS‏](https://academy.hsoub.com/files/14-التحريك-عبر-css/) - Donovan Hutchinson, Mohamed Beghat‏ (PDF)
 * [نحو فهم أعمق لتقنيات HTML5‏](https://academy.hsoub.com/files/13-نحو-فهم-أعمق-لتقنيات-html5/) - Mark Pilgrim, Abdullatif Eymash‏ (PDF)
-* [تعلم HTML](https://example.com/html-arabic) - مؤلف تجريبي (PDF)
 
 
 ### Introduction to Programming in Arabic
 
 * [مختصر دليل لغات البرمجة](https://alyassen.github.io/Brief-guide-to-programming-languages-v1.2.4.pdf) - Ali Al-Yassen‏ (PDF)
-* [تعلم C#](https://example.com/csharp-arabic) - مؤلف تجريبي (PDF)
 
 
 ### JavaScript
@@ -82,7 +80,7 @@
 ### Python
 
 * [البرمجة بلغة بايثون](https://academy.hsoub.com/files/15-البرمجة-بلغة-بايثون/)
-* [Learn Python](https://example.com/learn-python) - Test Author (PDF)
+
 
 ### Raspberry Pi
 
@@ -98,7 +96,6 @@
 
 * [تأمين الشبكات اللاسلكية للمستخدم المنزلي](https://mohamedation.com/securing-wifi/ar/) - Mohamed Adel‏ (HTML)
 * [دليل الأمان الرقمي](https://academy.hsoub.com/files/20-%D8%AF%D9%84%D9%8A%D9%84-%D8%A7%D9%84%D8%A3%D9%85%D8%A7%D9%86-%D8%A7%D9%84%D8%B1%D9%82%D9%85%D9%8A/)
-* [كتاب جديد](https://example.com/new-book) - أحمد علي (PDF, HTML)
 
 
 ### SQL

books/free-programming-books-en.md

@@ -8,7 +8,3 @@
 * [English, By Programming Language](free-programming-books-langs.md)
 * [English, By Subject](free-programming-books-subjects.md)
   (The list of books in English is here for historical reasons.)
-* [Learn Python](https://example.com/learn-python) - Test Author (PDF)
-* [تعلم HTML](https://example.com/html-arabic) - مؤلف تجريبي (PDF)
-* [Learn C#](https://example.com/learn-csharp) - John Doe (PDF)
-* [كتاب جديد](https://example.com/new-book) - أحمد علي (PDF, HTML)