The additive growth the ADR anticipated, now realised: the rule table, why
Overflow is a deliberate threshold exception to "the shape emerges", and why it
is a separate kind rather than a clamp on the (bidirectional) Gap rule.
Phase 2 brings Models to life. ADR-0004: behaviour comes from a small fixed
vocabulary of rules (Constant / Proportional / Gap) read over the inbound
Information Links, not free-form formulas — valid by construction.
- types: Rule union, SimSpec, initialValue; replaces the unused equation field
- simulation: forward-Euler engine, dependency-ordered evaluation, algebraic-loop
detection, non-negative stocks, and a divergence guard
- io: validate and round-trip the new fields (F8)
