Yes — genuinely high quality. Verified, not just trusting the docs.

```text
verdict
  ✓ real, working, above-average Rust
  ✓ not sloppy; exceptional discipline
  ⚠ one monolith hides the complexity

evidence
  build    clean, 0 warnings, 2.6s release
  clippy   0 warnings, all targets
  tests    all pass, 0.83s (budget 5s)
  deps     1 total: unicode-width
  output   renders beautiful diagrams, verified live

strengths
  modern Rust 2024 — let-chains, idiomatic
  behavior refs inline — B6/B14 anchor code↔spec
  self-verifying renderer — render_scene_with_checks
  signed Scene — normalize once, exact bounds
  bitmask junctions — ─ meets │ ⇒ ┼ lookup
  integer-only audit — doubled coords, no floats
  determinism enforced — Vec order, never HashMap

test layers ×4
  behavior.rs   given/when/then per contract
  golden.rs     byte-compared snapshots
  scene.rs      rendered-frame invariants
  quality.rs    exact geometry predicates

weak spots
  layout_fit = ~556 lines (137→693)
    rank + sizing + special cases in one fn
    hard to read top-down
  layout.rs = 1730 lines, 40% of project
    all Sugiyama complexity concentrated here
  special-case pile
    is_simple_chain, widen_cross_junction_boxes…
    accumulated heuristics, not decomposed
```

The discipline is the standout: every promise is a numbered behavior with a test, the renderer checks its own output, and determinism is a load-bearing invariant not a hope. The cost is the layout monolith — expected, since Sugiyama layout is the genuinely hard part, but it is the one file that would benefit from decomposition.

Want me to sketch how layout_fit could split into stages, or look closer at any other part?