This issue tracks the preserved local work parked before replacing the current checkout with a fresh Codeberg mirror.

Preserved branch:

• backup-pre-codeberg-refresh-2026-03-14
• commit 543c1739dc

Parked work includes:

• transitional .zag source support across compiler/file-discovery/import paths
• standalone .zag test coverage
• a broad set of local Zig 0.15.1 compatibility edits in test/*
• temporary macOS/test verification changes
• temporary runtime file addition lib/ubsan_rt.zig

Why this was parked:

• the current checkout appears based on Zig 0.14-era sources
• local host toolchain is newer and produced wide stdlib/runtime skew
• the plan is to refresh from Codeberg first, then re-apply only the pieces still wanted on top of the newer upstream base

Follow-up after refresh:

• verify the refreshed upstream toolchain baseline/version
• re-evaluate .zag support against the new compiler sources
• selectively cherry-pick or reimplement prior work instead of carrying forward stale compatibility patches

Parent issue: #4