v0.5.0

Highlights

• Migrates client.responses.compact(...) to explicit remote compaction v2 over the normal Responses stream while preserving the public SDK API.
• Adds the OAuth-authenticated Realtime v3 sideband transport for delegation and control events.
• Makes the confirmed Codex Realtime v3 contract canonical and supplies required session/thread correlation headers.
• Preserves prompt-cache write token usage reported by the backend.

Validation

• 221 tests passed.
• Remote compaction v2 verified live against the Codex OAuth backend with an encrypted compaction item and token usage returned.