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/49-hid/.gitignore

@@ -0,0 +1,16 @@
+# Build outputs
+.output/
+*.o
+*.skel.h
+hid-input-modifier
+
+# Editor files
+*.swp
+*.swo
+*~
+.vscode/
+.idea/
+
+# Temporary files
+*.tmp
+*.log