v0.3.4

Progress feedback: download bar + phase headers + verify counter

`run` was a long silent wait. Now it shows what's happening:
- Phase headers: [1/4] Model · [2/4] Benchmark · [3/4] Verify · [4/4] Submit.
- Model download: a live progress bar (bar, %, downloaded/total, speed, ETA)
  on a TTY; piped/CI output keeps the plain start/done lines.
- Verification: a "generating N/total (prompt, turns)…" counter, since the
  multi-turn llama-server pass is the slowest, opaque part.

All terminal-only drawing is gated on stderr.is_terminal() so logs aren't
spammed with carriage returns.