VS Code extension regression: @ picker no longer shows previous conversations since 26.727.40816

What version of the IDE extension are you using?

26.727.40816

What subscription do you have?

plus

Which IDE are you using?

vscode

What platform is your computer?

Microsoft Windows NT 10.0.19045.0 x64

What issue are you seeing?

VS Code extension regression: @ picker no longer shows previous conversations since 26.727.40816

What steps can reproduce the bug?

1. Install VS Code Codex extension 26.721.41059.
2. Open Codex chat.
3. Type "@" followed by a keyword matching an existing conversation title, e.g. "@ntp".
4. Previous Codex conversations appear in the picker and can be referenced.

1. Upgrade the extension to 26.727.40816 or newer.
2. Repeat the same steps.
3. Previous conversations no longer appear in the @ picker.

What is the expected behavior?

Previous Codex conversations should continue to appear in the @ picker so they can be referenced as context, as they did in 26.721.41059.

Additional information

Starting with 26.727.40816, previous conversations are no longer available in the @ picker.
Downgrading to 26.721.41059 restores the feature.