`cpSync` defaults to `dereference: false`, which means it tries to
recreate symlinks at the destination rather than copying file contents.
When a sensitive path (e.g. CLAUDE.md) is a symlink, this fails with
`ENOENT: no such file or directory, symlink` because `cpSync` attempts
to call `symlink()` without ensuring the parent `.claude-pr/` directory
exists first.
Adding `dereference: true` fixes this by following symlinks and copying
the actual file contents, which is also the correct semantic behavior —
review agents need to inspect the real content, not a symlink that may
not resolve correctly from `.claude-pr/`.
Fixes the action crash when repositories use symlinked CLAUDE.md
(e.g. CLAUDE.md -> AGENTS.md).
