Add HID-BPF tutorial and implementation for virtual mouse input modification

- Introduced a comprehensive tutorial in README.md explaining how to fix broken HID devices using eBPF without kernel patches.
- Implemented a userspace program (hid-input-modifier.c) that creates a virtual HID mouse using the uhid interface and sends synthetic mouse events.
- Developed a BPF program (hid-input-modifier.bpf.c) that intercepts HID events and modifies mouse movement data, effectively doubling the X and Y movement.
- Created necessary header files (hid_bpf.h, hid_bpf_defs.h, hid_bpf_helpers.h) to define structures and helper functions for the BPF program.
- Added functionality to find and manage the virtual HID device, ensuring seamless integration with the BPF program.

src/40-mysql/README.md

@@ -4,6 +4,8 @@ MySQL is one of the most widely used relational database management systems in t
 
 This is where eBPF (Extended Berkeley Packet Filter) comes into play. eBPF is a powerful technology that allows you to write programs that can run in the Linux kernel, enabling you to trace, monitor, and analyze various aspects of system behavior, including the performance of applications like MySQL. In this blog, we'll explore how to use eBPF to trace MySQL queries, measure their execution time, and gain valuable insights into your database's performance.
 
+> The complete source code: <https://github.com/eunomia-bpf/bpf-developer-tutorial/tree/main/src/40-mysql>
+
 ## Background: MySQL and eBPF
 
 ### MySQL