Custom chat titles not reliably shown in /resume and not synced across machines

Description

When using Claude Code with a shared CLAUDE_CONFIG_DIR on Google Drive (to sync config across multiple PCs), custom chat titles set via the tab rename feature have two issues:

1. Renamed chat title not reflected in /resume

After renaming a chat from the tab UI, the custom title does not appear in /resume. The custom-title entry is correctly written to the session .jsonl file:

{"type":"custom-title","customTitle":"Launch Claude","sessionId":"29e26940-ba97-4717-90fd-3efe57dc0f35"}

But /resume still shows the auto-generated title instead of the custom one.

2. Custom titles not synced between machines

When renaming a chat on PC-A, the title change is not visible in /resume on PC-B, even though the .jsonl file (containing the custom-title entry) is synced via Google Drive. This suggests /resume may be reading titles from a local cache or in-memory state rather than from the .jsonl files.

Environment

• Claude Code CLI (portable setup with CLAUDE_CONFIG_DIR on Google Drive File Stream)
• Windows 11, multiple PCs
• Config shared via Google Drive File Stream

Expected behavior

• /resume should show the custom title set via tab rename
• Custom titles should be visible on all machines sharing the same CLAUDE_CONFIG_DIR

Actual behavior

• /resume shows auto-generated titles, ignoring the custom-title entry in the .jsonl
• Titles set on one PC are not visible on another PC sharing the same config directory