docs: add odd_tests repository map

[sit-d]

Summary

• Add a root README for the odd_tests collection so visitors can quickly find the experiment that matches their task.
• Document the lack of a repository-wide build target and point to the smallest available per-experiment entry points.
• Include Linux-friendly validation notes for the Python converter while calling out Windows/fasm2/fasmg/toolchain requirements for assembly examples.

Verification

• python3 README link scanner: checked 32 local README links and all resolved.
• python3 -m py_compile cv2dwarf.py
• python3 cv2dwarf.py --help
• git diff --check

Notes / Limitations

• Documentation-only change.
• I did not run Windows/fasm2/fasmg assembly builds from the Linux cron environment; the README explicitly points readers to per-experiment scripts instead of claiming a repo-wide build.