fix(android/application): open windows after the original activity finishes - #11552

PR Checklist

• The PR title follows the commit guidelines.
• There is an issue for the bug: Android openWindow uses an undeclared Activity class after the original Activity finishes #11526.
• You have signed the CLA.
• All existing Core unit tests pass (544 passed, 1 skipped).
• Tests for the changes are included.

What is the current behavior?

After the original Android Activity finishes, startActivity can be cleared while a secondary NativeWindow remains usable. openWindow() then targets the hard-coded org.nativescript.NativeScriptActivity, which may not be declared in the manifest, and throws ActivityNotFoundException.

What is the new behavior?

Resolve the target from a live NativeScript Activity: the original Activity, the foreground Activity, or an attached surviving window. Exclude finishing/destroyed Activities, windows whose native surfaces are gone, and SDK Activities without the NativeScript marker. If none remains, use the application's configured launch component; report a clear error when it has no launch component instead of starting an undeclared class.

The existing window flags and payload delivery are preserved. This changes Android target selection only; there is no public API change.

Closes #11526.

Validation

• Added 10 regression cases for surviving windows, original/foreground Activity selection, SDK Activities, finishing/destroyed Activities, detached surfaces, configured launch components and the missing-launcher error. Against the original implementation, 9 of these cases fail.
• npx nx run core:test: 544 passed, 1 skipped, across 42 test files.
• npx nx run core:build: passed, before and after the fix.
• npx nx format:write --files=packages/core/application/application.android.ts,packages/core/application/open-window.android.spec.ts,packages/core/vitest.setup.ts: passed.
• Android 16 / API 36 arm64 emulator, NativeScript Android runtime 9.1.1, Core built from 3224f1b, com.tns.NativeScriptActivity, launchMode="standard": reproduced using an isolated native app with a window content resolver, without the router.

The native app opens a second window, finishes the original Activity, then requests another window from the survivor after activityDestroyed:

Before the final open request (both builds):
  startActivity=false, foregroundActivity=true, windows=1

Original Core:
  ActivityNotFoundException:
  {org.nativescript.openwindow11526/org.nativescript.NativeScriptActivity}

Patched Core:
  {"ok":true,"windows":2,"originalDestroyed":true,
   "payload":"after-primary-finished","flags":403177472}

The complete native automated app suite and an iOS simulator run were not executed locally. The native before/after check above and the full Core unit suite were executed.