* test: add test scripts for system calls

* feat: add visualization script for test results

* test: add `sdcard.img` binary

* feat: add Makefile for contest submission and testing environment

* chore: update .gitignore to exclude test artifacts and logs

* fix: update paths for test runner and visualization scripts in Makefile

* fix: remove unnecessary strip step from build process in Makefile

* fix: prevent Makefile clean command from failing on missing files

* feat: add preliminary grading workflow for CI

* fix: update Makefile to fix path issue

* feat: add README for preliminary test artifacts and visualizer script

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Co-authored-by: The most intelligent Cirno <9@caiyi1.me>