fix(hooks): don't abort init --status on an unreadable Cursor hook

show_claude_config read the Cursor hook file only to compute _is_thin, which
nothing reads. The `?` on that read meant an unreadable hook file aborted
`rtk init --status` before it printed the rest of the report -- a status
command failing on the thing it is meant to report about. The executable-bit
check above it is what the branch actually uses.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>