BEFORE — supplied lead evidence, retained verbatim below.
Real dev-server fixture transcript (base 3b95e7831b11b17627dff16843bc087bfca397ec):
main 3b95e7831b; Linux x64; vp run dev:server; port 13856; isolated .t3/userdata settings; fixture-only Codex homes
auth-fixture-a.json: symlink -> /tmp/issue8578-server-6e5s09zb/shared/auth-fixture-a.json
auth_fixture_b.json: symlink -> /tmp/issue8578-server-6e5s09zb/shared/auth_fixture_b.json
auth.json.bak: symlink -> /tmp/issue8578-server-6e5s09zb/shared/auth.json.bak
AUTH.Backup: symlink -> /tmp/issue8578-server-6e5s09zb/shared/AUTH.Backup
author.json: symlink -> /tmp/issue8578-server-6e5s09zb/shared/author.json
auth.json: regular file

Supplemental direct-helper transcript (not a dev-server run):
Fixture root: /tmp/issue8578-8Izp1Q
auth-fixture-a.json symlink -> /tmp/issue8578-8Izp1Q/shared/auth-fixture-a.json mode=600
auth_fixture_b.json symlink -> /tmp/issue8578-8Izp1Q/shared/auth_fixture_b.json mode=600
auth.json.bak symlink -> /tmp/issue8578-8Izp1Q/shared/auth.json.bak mode=600
AUTH.Backup symlink -> /tmp/issue8578-8Izp1Q/shared/AUTH.Backup mode=600
author.json symlink -> /tmp/issue8578-8Izp1Q/shared/author.json mode=600
auth.json regular file mode=600
Existing dangling auth-orphan.json symlink: accepted