[v0lumehi]

Fix or feature

• Fix
• Feature

What and why

While I shared my screen in Teams, windows popped up on my external monitor during swift test. The render and capture tests host SwiftUI views in titled windows at the origin and order them in. A titled window is also moved back onto a screen by AppKit, so even an offscreen frame does not hold for it.

This adds one test helper, OffscreenWindow in frontend/Tests/NX2AppleTests/OffscreenWindow.swift. It sits at (-100000, -100000), is never key or main, and is put back offscreen after the initializer moved it. It is still ordered in, so layout and cacheDisplay work as before. The titled style stays the default because the launcher draws under its transparent title bar. Every NSWindow(contentRect:...) in the tests that is shown now uses it (16 files). setActivationPolicy(.accessory) calls stay. No product code changed.

One side effect: the captures of a 1440x1024 window were cut to the height of the screen before (992 pt on my Mac). They are now the full 1024 pt, so the PNGs no longer depend on the display.

Checked

• Tests: cd frontend && swift test: 703 tests, 17 skipped, 0 failures, and the pre-push hook passed.
• Test for a fix: OffscreenWindowTests.testRenderWindowsAreNeverOnAnyDisplay orders in a titled, a borderless and a resizable helper window and asserts that none is on a display, for AppKit (NSApp.windows against NSScreen.screens) and for the window server (CGWindowListCopyWindowInfo). I also ran the whole suite once with a temporary observer that did the same check after every test. It found no window on a display (537 checks). The observer is not in the PR.
• Visual QA: NX_LAUNCHER_CAPTURE_DIR captures (78 PNGs) and the console captures (24) before and after. Console captures and 47 launcher captures are identical. The others differ only in the random temp path text, or in height as described above. ConsoleTests.testFirstTileRingIsNotClippedAfterScrollingBack passed in every run.
• Run on a device or Mac: not needed.
• Not checked: I cannot see the screen, so the check above is by API, not by eye.

Screenshots

None, no visible change.

Scope

• No engine file (dm/, scripts/, docs/, ref/) is added to the repository
• A fix to the engine or a game profile also goes to seedds/nxnative as a PR in parallel: not an engine change
• A change to a launcher view has before and after screenshots above: no view changed
• No keys, game files or data extracted from a game in the change or the attachments