Desktop app: New Chat routes prompt into last active chat instead of starting fresh

Description

On the desktop app, clicking "New Chat" from the menu (first option in the last menu) does not start a new conversation. Instead, the next prompt I type gets routed into my most recent/last active chat session.

Platform behavior difference

• Desktop app: broken — cannot initiate a genuinely new chat this way.
• iOS app: works correctly — New Chat actually starts a fresh conversation.

Expected behavior

Clicking New Chat should always start a new, empty conversation, regardless of what chat was last active.

Actual behavior

The prompt gets appended to the previous chat session instead.