H-103 dependency / firewall chain
=================================

Exact field chain retained unchanged:
- h049_numerical_instrument_convergence.py
    inherited p=0 direct finite Dirichlet/DST field solver, fractional spherical
    source sampler, and complete finite-difference RHS
- h062_gr_required_node_route_attack.py
    FrostCell corner geometry/all-eight affine frame helper via H-102 only
- h088_signed_residual_finite_cell_attack.py
    frozen K / p=0 constants only
- h100_single_high_r_tail_probe.py
    memory-lean exact R65 allocation, already validated bit-for-bit
- h102_local_radial_shell_template_audit.py
    exact FrostCell/FrostSegment geometry helpers and exact-field builder only

H-103 adds measurement/reconstruction shadows only:
- inherited perfect-sphere source cubic-symmetry audit;
- u_x odd/even/y-z exchange symmetry audit;
- canonical u_x wedge reconstruction shadow;
- 48 signed-axis-permutation vector covariance audit;
- 48-fold 12-FrostSegment length/tilt covariance audit;
- exhaustive complete-RHS symmetry audit at manageable R;
- diagnostic cubic-orbit-averaged source shadow if the inherited fractional
  sampler has a numerical symmetry residue;
- exact storage-count projections for positive octant and tight component wedge.

No GR scorer is called. No photon path is generated. No radial/q4/q6 model feeds
the exact field. The symmetrized-source diagnostic never replaces inherited FV.
No gravity/node mechanics are changed. Planetary/Jupiter holdouts remain sealed.
