@fix spec v2.0: metamaterial upgrade + formal corrections + complete grammar

Major revision addressing domain expert review (7 CRITICAL, 9 HIGH) and
Marcus Chen architectural review (metamaterial vs katana).

Metamaterial upgrade:
- Nested @fix with constraint escalation (L1 outer containing bounded L2 inner)
- L1/L2 IR type separation (non-convergence unrepresentable at L1)
- L2 reframed as generative layer (abductive), not "L1 with restrictions relaxed"
- Enriched category structure named (Section 1.5: forgetful functors, adjunctions)
- Universal property (initial algebras / final coalgebras via Lambek's lemma)
- Composition rules (constraint levels as total order, join on composition)

Formal corrections:
- Knaster-Tarski: finite ascending chain condition, lattice explicitly defined
- Curry-Howard: scoped to verifiable certificate with precise verification algorithm
- Gurevich-Shelah: expressive power equivalence, not operational equivalence
- L2 TC: grounded in Abiteboul-Hull-Vianu 1995
- Determinism: fixpoint unique, delta sequence may vary with rule order
- Closed domain: precise definition replacing vague "no value invention"

Grammar completeness:
- All productions defined (path_pattern, yield elements, timeout, measure)
- Examples parseable by grammar as written
- || → or (avoids conflict with existing alternative marker)
- stable formally defined (δ = ∅)

New: E010 (unstratifiable negation), E011 (nesting de-escalation)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: phillipclapham