Clean up deprecated runtime surface after v0.4.0

[bbopen]

Clean up the remaining deprecated runtime surface after v0.4.0 so new examples and docs reflect the public API rather than compatibility shims.

Acceptance Criteria

• deprecated aliases and options are documented with a clear removal path
• new examples avoid deprecated APIs and compatibility-only imports
• any removals that should wait for a later major release are explicitly deferred and documented as such