New 536-line documentation file describing:
- Purpose and responsibility of each src/ subdirectory
- Module dependency order and include structure
- Directory health status with action items
- Cleanup plan for dead code and duplicates
- Design principles and future architecture roadmap
Documents all active modules (topology, basis, quadrature, mesh, materials,
assemblers, domains, solvers, physics, etc.) and identifies legacy/duplicate
code that needs cleanup.
Jukka Aho