~anthropic/claude-sonnet-latest → A (3:2)

Side A performs a broader architectural cleanup: splitting canonical_path/identity concerns, enforcing strict wire-form validation (rejecting `@` in API input), and consistently updating CLI/server/tests/types to match, which reduces ambiguity and hardens the API surface. Side B fixes a real but narrower bug (tilde ontology root normalization) with good test coverage, but its scope and lasting design impact are smaller than A's systemic identity/wire-format rework.