Session title language should respect CLAUDE.md language settings

Feature Request

Session titles in the left sidebar are always generated in English, even when the user's CLAUDE.md specifies a non-English language (e.g., 日本語で応答する / "respond in Japanese").

Current Behavior

Session titles are auto-generated in English regardless of language configuration. For example, a session about meeting notes in Japanese gets titled "Meeting digest processing" instead of something like "会議メモの整理".

Expected Behavior

Session titles should respect the language specified in CLAUDE.md or the primary language of the conversation, so they are more meaningful and easier to identify for non-English users.

Context

For users who work primarily in a non-English language, English session titles make it harder to quickly identify sessions in the sidebar. This is especially impactful for users with many concurrent sessions.

Suggested Solution

• Use the language setting from CLAUDE.md (if present) when generating session titles
• Or detect the primary conversation language and generate titles accordingly