Sidebar peek: the ProjectSwitcher menu detaches and floats when the peeked sidebar closes

[aleexzxzxzx]

Problem

The collapsed-sidebar hover-peek (#3367) has a rough edge around the ProjectSwitcher
card at the bottom of the sidebar.

With the sidebar collapsed and peeked (revealed as a floating overlay by moving the
cursor to the left edge), opening the ProjectSwitcher menu and then moving the cursor
off the panel collapses the sidebar — but the menu, rendered in a portal anchored to
its trigger, stays open. It's left floating over the content and shifts as its anchor
slides away. The submenus (Project, Organization) make it worse: they fly out to
the right, past the peek's close margin, so hovering them dismisses the peek while the
menu is still open.

Steps:

1. Collapse the sidebar (Cmd/Ctrl+B).
2. Move the cursor to the left edge so the sidebar peeks out.
3. Click the ProjectSwitcher card (project name + email) to open its menu.
4. Move the cursor away, or onto a submenu that opens to the right.

Expected behavior

• The peek should stay open while a menu spawned from the sidebar is open, regardless
  of cursor position.
• Once the menu closes, the peek returns to normal: it collapses on the next
  directional exit, matching the existing hover-peek behavior.

I have this fixed locally, opening a PR now.