[eagleoflqj]

Replace the launch placeholder with a Discover screen that checks for available iOS simulators, lists their runtime and power state, and provides setup guidance when none exist. Offer Xcode installation through the App Store when Xcode is missing, distinguish toolchain errors from an empty inventory, and open Device Hub or Simulator from the selected Xcode installation. Refresh on app activation, with the refresh button, or with Command-R.

Keep branding, navigation, and the repository link visible while long simulator lists scroll independently. Constrain both split columns to the window viewport, keep the toolbar status inside its background, and center discovery states across the whole detail area. The empty-state illustration uses the tablet and phone without a button-like plus badge.

Separate the sidebar, no-simulator guidance, missing-Xcode guidance, and discovery status views into dedicated SwiftUI files. Keep window composition, discovery state, and action handling in ContentView.

Validation:

• CMake/Ninja Release build and strict swift-format checks passed.
• All four CTest checks passed: visible app window, exit after closing the last window, simulator discovery, and bundle SDK/minimum OS metadata.
• Discovery tests cover empty/malformed inventories, available iOS filtering, power states, command errors, Device Hub and Simulator paths, missing Xcode, and incomplete Xcode setup.
• GUI preview with 40 fixture devices and long names passed at 900×600 and 1180×780, including scrolling to the final device with navigation fixed. The no-device state also fits the minimum window without overlapping its header.