fix(core): reject oversized QR matrices

[ubugeeei]

Summary

• reject matrix sizes outside the QR version 1-40 range before deriving a version
• add regression coverage for oversized congruent matrix sizes that previously wrapped

Closes #1

Validation

• cargo test -p fastqr-core

[ubugeeei]

Landed via #27 after local vp run ci and final GitHub Actions CI passed. Closing this issue-scoped PR to keep the queue and PR list clean.