When reopening windows (last_session), open them all at once

[road2react]

Check for existing issues

• Completed

Describe the feature

Currently, if there were a lot of windows opened in last session, opening Zed again causes them to open one at a time, often with 1-2 seconds in between, stealing focus

Ideally, they should all open at once and deal with loading at the same time (like VSCode)

Environment

Zed: v0.162.5 (Zed)
OS: Linux Wayland arch unknown
Memory: 93.5 GiB
Architecture: x86_64
GPU: AMD Radeon 680M (RADV REMBRANDT) || radv || Mesa 24.2.7-arch1.1

If applicable, add mockups / screenshots to help present your vision of the feature

No response