Support Blueprint boolean constraints

[razor-x]

Summary

• update @seamapi/blueprint to 1.6.0
• generate Literal[True] and Literal[False] for constrained booleans
• preserve unconstrained booleans as bool and multiple values as Literal[...]
• merge boolean constraints across flattened variants and regenerate the SDK
• add regression coverage for access-code union narrowing and opposite-literal rejection

Verification

• npm run typecheck
• npm run lint
• just lint
• just test (162 passed)