Feature Request: Enable thinking.display for Claude Code subscription sessions

API users can set thinking.display: "summarized" to receive summarized reasoning content from Claude models with adaptive thinking. Claude Code has a showThinkingSummaries setting (visible in the settings schema) but the server does not honor the thinking.display parameter for subscription-authenticated sessions — only API key sessions receive thinking content.

Use case

As AI-generated code enters production systems, developers need to understand why the model made specific decisions — not just what it output. Debugging AI-authored code without access to the reasoning that produced it is like debugging a binary without source. This is especially relevant as agent workflows scale: Uber reported 11% of their live backend code is now AI-generated, and that number is climbing.

Summarized thinking content would enable:

• Post-session audit of model reasoning for critical code changes
• Debugging when AI-generated code produces unexpected behavior
• Compliance and explainability in regulated environments where automated decisions require documentation
• Developer learning by understanding how the model approaches complex problems

Current behavior

• CC sends redact-thinking-2026-02-12 as an anthropic-beta header by default
• When showThinkingSummaries is enabled in settings, CC removes the redact flag and sets thinking.display: "summarized" on the request
• The server returns a thinking block with an empty thinking field and a signature (used for token accounting)
• The same request structure returns summarized thinking text for API key sessions

Requested behavior

Honor thinking.display: "summarized" for CC subscription sessions the same way it is honored for API key sessions. The showThinkingSummaries setting already exists in CC — the server just needs to return the content.

Context

This is not about exposing raw chain-of-thought. The "summarized" display mode already exists and produces concise reasoning summaries appropriate for developer consumption. The infrastructure is built — it just needs to be enabled for subscription auth.