feat: add schema-shaped operation facades

[sourishkrout]

Summary

• adds schema-shaped Owl operation facades backed by the graph
• routes read, mutation, type suggestion, and project spec flows through GraphQL
• moves internal store machinery to internal/state.Machine and removes obsolete public helpers
• keeps CLI on pkg/owl/... APIs, including type catalog root selection

Verification

go test ./...
make check
runme run test
runme run lint