Three source-audit findings on 81b7f42, fixed:
1. Slur kind and line style were dropped at projection and every slur drew
solid with no signal. SlurContent now carries `kind` (SlurKind) and `line`
(LineStyle) through the projection, and a non-Solid authored line style
emits a `LayoutDiagnosticKind::SlurLineStyleNotRendered` — the curve still
draws (solid, ink + provenance kept), but the ignored dash/dotted intent is
surfaced, not papered over. The Minimal tier still draws one canonical arc
per kind (kind-aware rendering is higher-tier); the kind is now preserved
for it. The slur fixture's editorial slur is authored Dashed to exercise it.
2. Curve hit-testing flattened to a fixed 16 chords and tested capsules at
exactly half_width, so a thin/high-curvature slur's true ink between samples
could miss a click. contains/intersects_rect now inflate the capsule by a
proven flattening-error bound (h²/8·max‖B''‖ = (3/4N²)·max second-difference)
— provably conservative, so a click on the drawn arc never misses. The AABB
(control hull ± half_width) already bounds the true ink, unchanged.
3. The engrave crate-level doc still said "no drawn slur geometry exists yet";
updated to slur_shape 0.0 by construction (Minimal draws the ideal arc),
beam_slope still vacuous.
931 tests, docs clean, conformance 8/8. Zero golden churn (dashed slur draws
solid; layout diagnostics don't reach the render output).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>