feat: Add multi-agent command center grid view

[charlesvien]

Inspired by https://x.com/karpathy/status/2031616709560610993?s=46

This is exactly how I use Ghostty w/ Claude Code and if I could do this in Code + now we have skills support... it would be magical to say the least. I could follow this up with tab support in each of the panels so you can interact with shells for each and stuff? LMK thoughts code folks!

If you guys are onboard and we manage to merge this, I'd love to demo this on Monday because I think this would drive some internal adoption.

1. Add command center grid view with configurable layouts (1x1 through 3x3) and zoom controls
2. Support drag-and-drop task assignment onto grid cells with swap behavior for occupied cells
3. Add per-cell session views with status badges, toolbar with stop-all/clear actions and agent summary
4. Extract useSessionCallbacks and useSessionConnection hooks from TaskDetail for reuse
5. Add compact mode to SessionView/ConversationView for tighter grid rendering
6. Wire command center into MainLayout as a new "command-center" view type

[charlesvien]

• fix: Reduce agent eagerness to re-enter plan mode mid-task #1208
• feat: Scope oauth tokens by org, replace flat project list with org-keyed map #1210
• feat: Add multi-agent command center grid view #1212 👈 (View in Graphite)
• feat: Add effort level control for Claude sessions #1211
• feat: Optimistically render conversation items before subscription confirms #1209
• feat: Add idle timeout to kill inactive sessions after 15 minutes #1207
• fix: Fix corrupted view redirect, workspace cache flash and diff collapse #1206
• main

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[jonathanlab]

awesome

[charlesvien]

Merge activity

• Mar 12, 10:49 PM UTC: A user started a stack merge that includes this pull request via Graphite.
• Mar 12, 11:05 PM UTC: Graphite rebased this pull request as part of a merge.
• Mar 12, 11:10 PM UTC: @charlesvien merged this pull request with Graphite.