Natural follow-up to --audit-tree: when that utility flags
ext-mismatch or magic-no-ext issues, --magic-fix proposes (and
optionally applies) the renames that resolve them. Walks a
directory recursively, reads each file's 4-byte magic, looks it
up in the format table, and renames to the canonical extension
when the current extension doesn't match (or is absent).
Defaults to dry-run for safety — prints the proposed renames so
they can be reviewed first; pass --apply to commit them. Refuses
to clobber existing files: when the target path already exists
(e.g. foo.wsct + foo.wsrg both with WSRG magic), the rename is
flagged as a collision and skipped, leaving both files in place
for manual resolution. Returns exit 1 if any proposals exist (in
dry-run) or any collisions are skipped (in apply), so it composes
into shell pipelines.
JSON sidecar via --json. Suggested workflow:
--audit-tree dir # find what's broken
--magic-fix dir # preview the auto-fixes
--magic-fix dir --apply # commit them
--audit-tree dir # confirm clean
CLI flag count 921 -> 922.
