test(phpstan): enable PHPStan level 3 for some of Pages/

[JohnVillalovos]

Resolve PHPStan level 3 issues found when enabling checking of the Pages/ directory, excluding 'Pages/Admin/andPages/Ajax/`

[Copilot]

Pull request overview

Enables stricter PHPStan (“next” config) checking for most of the Pages/ layer by narrowing the exclusion list, and resolves resulting level 3 type issues mainly by making page input getters return consistent scalar/array types.

Changes:

• Update phpstan_next.neon to include Pages/ in level 3 analysis while excluding only Pages/Admin/ and Pages/Ajax/.
• Normalize several Pages/* getters to return int, float, string, or int[] consistently via explicit casting / array normalization.
• Align a few interface/PHPDoc return types (and a related test fake) with the now-enforced types.

Reviewed changes

Copilot reviewed 20 out of 20 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tests/Presenters/UserCreditsPresenterTest.php	Updates fake page getters to match stricter int return types.
phpstan_next.neon	Adjusts exclusions so PHPStan level 3 runs on most of Pages/.
Pages/SearchAvailabilityPage.php	Normalizes resource-related form inputs to int / int[].
Pages/Search/SearchReservationsPage.php	Normalizes form inputs (user/resources/schedules) to int / int[].
Pages/SchedulePage.php	Casts schedule/resource/filter query params to int for consistent typing.
Pages/Reservation/ReservationPage.php	Corrects property PHPDoc to IPermissionServiceFactory.
Pages/Reservation/NewReservationPage.php	Updates PHPDoc return types to allow `Date
Pages/Reports/SavedReportsPage.php	Casts report id query param to int.
Pages/Reports/CommonReportsPage.php	Casts report id query param to int.
Pages/MonitorDisplayPage.php	Casts schedule/day/resource query params to int.
Pages/LoginPage.php	Ensures password getter returns a string.
Pages/Install/InstallPage.php	Ensures install password getter returns a string.
Pages/IPageable.php	Ensures paging getters return int consistently.
Pages/GuestParticipationPage.php	Fixes email getter signature/return to string.
Pages/Export/EmbeddedCalendarPage.php	Casts “days to show” query param to int.
Pages/Export/CalendarSubscriptionPage.php	Casts subscription day-range/accessory inputs to int.
Pages/Export/CalendarExportPage.php	Fixes accessory name getter signature/return to string; casts ids to int.
Pages/Export/AtomSubscriptionPage.php	Casts subscription day-range query params to int.
Pages/Credits/UserCreditsPage.php	Updates paging getters to int and normalizes numeric query params.
Pages/CalendarPage.php	Corrects URL factory PHPDoc return type to CalendarUrl.