Add AppleSiliconAdapterEvidence normalization design and fixtures

Adds AppleSiliconAdapterEvidence normalization design, raw and normalized dry-run fixtures, Makefile JSON validation, and repo maturity updates.

This is docs/fixtures/validation only and introduces no host mutation, Secure Enclave calls, disk writes, installer execution, rollback execution, or runtime behavior change.

Closes #15.

Author: mdheller