[FEATURE] Localize auto-generated session titles in "Recents" sidebar

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

The auto-generated session titles in the "Recents" sidebar of Claude Code Desktop are always in English, even when all my prompts and the OS UI are in Japanese.

Examples currently shown in my Recents:

• "Find mapo tofu restaurants in Hiroshima"
• "Convert bank statement to Excel format"
• "Update investment data"

For non-English users, English titles make the Recents list significantly harder to scan at a glance, slowing down session navigation.

Environment:

• Claude Code Desktop App on Windows 11 (Japanese UI)
• Model: Claude Opus 4.7
• All prompts written in Japanese

Proposed Solution

Either of the following would address this:

1. Auto-detect the dominant prompt language of each session and generate the title in that language.
2. Provide a settings.json option (e.g. "sessionTitleLanguage": "ja") or environment variable to fix the title language.

Additionally, a manual rename option via right-click context menu in the Recents sidebar would be a useful fallback.

(日本語要旨)
日本語でプロンプトを書いていてもRecentsのタイトルが英語生成されるため、プロンプト言語追従または言語固定設定があると助かります。手動リネーム機能の追加も歓迎です。

Alternative Solutions

_No response_

Priority

Medium - Would be very helpful

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_