Implements the Electron host required by ICS-11798.
- Adds an independent fullscreen BrowserWindow on the first non-primary display.
- Adds typed preload APIs for display discovery, open/close, snapshots and topology changes.
- Retains snapshots during renderer loading and safely tears down on display changes.
- Keeps the capability optional in the public ElectronApi type so existing app mocks remain source-compatible.
- Lazily initializes the native host, leaving display listeners and windows completely dormant in kiosk and other consumers until they call the capability.
- POS/Android implementation: https://gitlab.icssolution.com/back/pos-app/-/merge_requests/73
Validation: TypeScript check, formatting/lint, package build and the full test suite passed (151 passed, 1 skipped). Kiosk's existing createMockElectronApi type-checks unchanged against the generated package declaration.