Parameter names are inconsistent across materials; K means three different quantities

[petlenz]

Same key, different physics

• K is the bulk modulus in the elastic/plastic materials and the hardening modulus in linear_isotropic_hardening; K_bulk and K_inf (a saturation stress) also exist. docs/plasticity.md shows "K": 1000 and "K": 166.67 nine lines apart. Swapping them builds, runs, and gives plausible numbers.

Same concept, different keys

• strain_producer_name vs strain_source
• solver_name / solver_source / integrator_source / function
• _name vs _source suffixes generally, plus a bare source
• tangent_source vs tangent_sources
• kappa_0 / kappa_f / kappa_critical
• "m_direction" / "n_direction" (member-style prefix in a user-facing key)
• "value" vs "state"

Proposal

Pick one convention (<thing>_source for wiring, physical symbols without prefixes for constants, H for a hardening modulus) and accept the old keys as deprecated aliases that warn once, so existing decks keep working. Renaming is breaking; the aliases are what make it safe to do incrementally, one material at a time.

All references are to main at 91bd26f.