E01 · F01 · EN-005 — Local proportional radius clamp

Compute the effective radius of every vertex from the requested radii (DERIV-local-radius-clamp steps 2 and 3, ADR-0007).

Acceptance criteria

Sources: DERIV-local-radius-clamp (check table), principle of REF-CSS-BR §4.5, edge length by REF-MATHWORLD-VECTOR-NORM (SP-001).

Given a 100 × 100 square with radius 1000 on one corner and 0 elsewhere, when clamped, then the effective radius of that corner is 100.
Given an edge of length 25 between two right corners with radius 100, when clamped, then both effective radii are 12.5 within EPSILON (the float result is 12.500000000000004).
Given a 100 × 100 square with radius 50 on every corner, when clamped, then every effective radius is 50.
Given aligned vertices with radius 30, when clamped, then no setback is produced (s = 0).
Given a rectangle of size 0 × 50 (Q15), when clamped, then no NaN appears and no setback is produced: S ≤ L is tested before dividing (L = S = 0 gives f = 1).

Float results are compared within EPSILON = 1e-9 (Q10).

One task = one commit, referenced as EN-005.Tn.

T1 — EPSILON (Q10) and edge length norm (math, REF-MATHWORLD-VECTOR-NORM) with their tests (0.5 h)
T2 — Generalize cyclicVertex into cyclicItem, used for vertices and for per-vertex numbers (geometry) (0.5 h)
T3 — Corner (vertex and requested radius), setbacks, edge lengths, factor per edge (geometry, DERIV-local-radius-clamp steps 1–2) with the check table (1 h)
T4 — Factor per vertex and effective radii (geometry, step 3); properties: 0 ≤ effective ≤ requested, setbacks of an edge ≤ its length (1.5 h)
T5 — Audit findings: turningAngle gave π on a zero-length edge after a negative incoming vector (signed zeros), now 0 explicitly; factor ranges [0, 1]; independent setbacks in the overlap property (1 h)