Sidebar Loops: active loops first, open by default, and it follows Tasks instead of floating to the bottom

[pallaoro]

What changes

• The sidebar Loops list shows enabled loops first and paused ones after.
• The Loops accordion starts open, like Projects and Tasks.
• Loops no longer floats to the bottom of the sidebar. It stacks directly under Tasks, so collapsing Tasks brings Loops straight up. Each open accordion still grows with the existing flex rule, capped at its content.
• Mission Control's Loops mode follows the same active-first order, keeping its "follows the sidebar list" behavior.

The Loops tab keeps the engine's order, so a loop does not jump when toggled there.

Verified

• Dev app over CDP: with Tasks collapsed, the Loops header sits directly under the Tasks header.
• Renderer typecheck passes. Desktop tests pass.