fix(ai): default responses to encrypted reasoning - #44863

Summary

• default the provider-neutral Open Responses route to store: false and include: ["reasoning.encrypted_content"]
• explicitly apply the same defaults to the independent OpenAI and xAI Responses routes
• preserve request-level storage overrides and include: [] opt-outs
• update inherited route assertions, WebSocket payload expectations, and affected recorded request fixtures

Why

Stateless Responses conversations can replay prior reasoning only when the provider returns encrypted reasoning state. Requesting it consistently prevents reasoning from being dropped on tool-result and follow-up requests.

Verification

• bun run typecheck
• 123 focused OpenAI, compatible Responses, and xAI tests
• 9 affected recorded/provider tests
• 2 inherited provider-default tests

Unrelated existing Anthropic provider-package and recorded PDF failures reproduce on the unmodified baseline and are outside this PR.