* feat(ADR-0167/W1-A): MathReaderRefusalEvidence schema + canonical-bytes
Foundation type for routing comprehension-reader refusals into the
teaching corridor. Frozen dataclass with sha256 evidence_hash computed
from deterministic canonical bytes (mirrors state.to_canonical_bytes
pattern). Includes SUB_TYPE_FOR_OPERATOR mapping table covering all 13
missing_operator values in the current audit artifact.
Wave 1 only — no runtime mutation, no teaching-store integration, no
admission path. Downstream W2-A/B/C/D type-import from this module.
* feat(ADR-0167/W2-C): domain discriminator + cross-domain audit
- Links to the audit doc: docs/handoff/ADR-0167-W2C-cross-domain-audit.md
- Inventory details: 5 construction sites, 8 consumption sites
- Verification: 0 cognition test files were modified; all tests are green
- Downstream partition work flagged: contemplation indexing (in teaching/contemplation.py) and replay gate (in teaching/proposals.py)
