Advanced Fuzzing and Image Injection for the Kernel and erofs-utils

I plan to focus on three concrete deliverables during GSoC: an advanced fuzzing tool, an image injection tool, and a new GitHub Actions workflow for periodic fuzzing. My goal is not only to implement these components, but also to make them understandable, reproducible, and genuinely useful for long-term EROFS development. The expected implementation order is to first establish a format-aware fuzzing workflow, then build an image injection tool that helps reproduce and analyze specific issues, and finally connect the resulting workflow to periodic CI-based robustness testing.