# bf-360: --check subcommand verification

## Task

Implement `--check` subcommand in claude-print.

## Status

Already implemented in commit `50b2132` (Phase 9: NEEDLE integration).

## Verification

Ran `./target/debug/claude-print --check` on this system:

```
CHECK                RESULT DETAIL
------------------------------------------------------------------------
openpty              PASS   openpty() syscall succeeded
mkfifo               PASS   mkfifo succeeded (dir: /home/coding/.tmp)
mock_claude PTY      PASS   PTY round-trip OK — isatty=true in child (/home/coding/.local/bin/mock_claude)

All checks passed.
Exit code: 0
```

## Implementation

- `src/check.rs` — `run()` function with three probes:
  - `probe_openpty()`: calls `openpty(None, None)`, drops handles, returns PASS/FAIL
  - `probe_mkfifo()`: creates a named FIFO in `$TMPDIR`, cleans up, returns PASS/FAIL
  - `probe_mock_claude_pty()`: optional; forks, execs `mock_claude` in a PTY slave via `login_tty`, waits up to 5s for exit 0
- `src/cli.rs` — `--check` flag wired into `Cli` struct
- `src/main.rs` — `if cli.check { let code = claude_print::check::run(); process::exit(code); }`
- `src/lib.rs` — `pub mod check;` exported

All acceptance criteria met: cargo build succeeds, `--check` exits 0 with diagnostic table, missing `openpty` would exit 2 with FAIL row.