Summary

Adds a Codex.app-like workspace launcher entry for Browser Workspace in the Electron desktop client.

This is an entry-point and placeholder PR only. It does not connect a real BrowserView/WebContentsView yet.

What Changed

• Add /browser desktop route.
• Add a Browser Workspace placeholder page.
• Add a centered workspace launcher with File, Side Chat, Browser, Review, and Terminal cards.
• Make only the Browser card active; other cards are inactive/coming soon.
• Add Cmd+T navigation to the Browser Workspace placeholder.

Validation

• npm run type-check --workspace apps/desktop — PASS
• npm run build --workspace apps/desktop — PASS
• npm run test:desktop:platforms --workspace apps/desktop — 79 PASS
• Electron dev manual check:
  • Browser card opens /browser
  • Placeholder shows read-only Browser Workspace messaging
  • Inactive cards do not trigger actions

Scope

• Desktop UI entry point only.
• No BrowserView/WebContentsView integration yet.
• No browser-host/backend changes.
• No executors/Kanban changes.
• No web dashboard changes.