feat(mat): ADR-144 UWB range-constraint fusion (#848)

- mat/localization/range_constraint.rs (forward-looking; no UWB hw yet):
  - RangeConstraint domain model (anchor_id/pos/measured_range/uncertainty/
    signal_quality); predicted_range/residual/mahalanobis/is_consistent
  - RangeConstraintFusion::refine() — Newton-normalized weighted least-squares
    that constrains a CSI/CIR prior toward range spheres, Mahalanobis-gates
    inconsistent (NLOS/multipath) ranges; returns RefineResult with rejected
    anchors + RMS residual
  - associate() disambiguates which track a range belongs to (re-ID hook)
- 4 tests (converges to truth, absurd range gated, consistency math, track
  association); workspace 0 errors

Co-Authored-By: claude-flow <ruv@ruv.net>