Upgrade PHPStan to 2.x and raise analysis level from 6 to 10

- Bump phpstan/phpstan ^2.0 and szepeviktor/phpstan-wordpress ^2.0
- Move the analysis level into phpstan.neon (single source) and raise it to 10
- Add Val, a runtime coercion helper that narrows untyped WordPress boundary
  values (wpdb rows, REST params, superglobals, options) with explicit checks
  instead of blind casts, plus unit tests
- Type value-object fromRow() params as stdClass (what wpdb returns) and map
  columns through Val so unexpected shapes degrade safely
- Use %i identifier placeholders for table names in all wpdb::prepare() calls
  so every query string is a literal and identifiers are escaped by WordPress;
  raises the minimum WordPress version to 6.2 where %i was introduced
- Guard wpdb::prepare() null result before wpdb::query() in updateTax()
- Fix nullable get_permalink()/strtotime() handling, list types at REST and
  capability call sites, dead null-coalescing on checked superglobals, and
  narrow get_users() results before mapping
- Register Val method names with the ValidatedSanitizedInput sniff so it
  validates the real sanitizer around each superglobal read
- Update repository unit tests for the %i placeholder arguments

Co-Authored-By: Claude Fable 5 <[email protected]>

src/Booking/BookingEndpoint.php

@@ -10,6 +10,7 @@ use Unsupervised\Schedular\Payment\Payment;
 use Unsupervised\Schedular\Payment\PaymentService;
 use Unsupervised\Schedular\Policy\PolicyAcceptance;
 use Unsupervised\Schedular\Registration\RegistrationGate;
+use Unsupervised\Schedular\Val;
 
 class BookingEndpoint {
 
@@ -27,6 +28,11 @@ class BookingEndpoint {
 		private PaymentService $payments,
 	) {}
 
+	/**
+	 * Registers this endpoint's REST routes.
+	 *
+	 * @param non-falsy-string $route_namespace REST namespace the routes are registered under (e.g. `us-scheduler/v1`).
+	 */
 	public function registerRoutes( string $route_namespace ): void {
 		register_rest_route(
 			$route_namespace,
@@ -103,7 +109,7 @@ class BookingEndpoint {
 	}
 
 	public function book( \WP_REST_Request $request ): \WP_REST_Response|\WP_Error {
-		$slotId = (int) $request->get_param( 'slot_id' );
+		$slotId = Val::int( $request->get_param( 'slot_id' ) );
 		$slot   = $this->availability->findById( $slotId );
 
 		if ( null === $slot ) {
@@ -120,7 +126,7 @@ class BookingEndpoint {
 		// used must belong to the slot's instructor. This prevents substituting a
 		// cheaper/free offering to dodge payment, or another instructor's offering
 		// to misroute it.
-		$requestedOfferingId = absint( $request->get_param( 'offering_id' ) );
+		$requestedOfferingId = absint( Val::int( $request->get_param( 'offering_id' ) ) );
 		$slotOfferingId      = (int) ( $slot->offeringId ?? 0 );
 
 		if ( $slotOfferingId > 0 ) {
@@ -142,7 +148,7 @@ class BookingEndpoint {
 		}
 
 		$answers            = $this->answers( $request );
-		$acceptedVersionIds = array_map( 'absint', (array) $request->get_param( 'accepted_policy_version_ids' ) );
+		$acceptedVersionIds = array_values( array_map( static fn( mixed $v ): int => absint( Val::int( $v ) ), (array) $request->get_param( 'accepted_policy_version_ids' ) ) );
 
 		$gateError = $this->gate->validate( $offeringId, $answers, $acceptedVersionIds );
 		if ( $gateError instanceof \WP_Error ) {
@@ -150,7 +156,7 @@ class BookingEndpoint {
 		}
 
 		$studentId  = get_current_user_id();
-		$notes      = (string) $request->get_param( 'notes' );
+		$notes      = Val::string( $request->get_param( 'notes' ) );
 		$recurrence = Lesson::RECURRENCE_WEEKLY === $request->get_param( 'recurrence' )
 			? Lesson::RECURRENCE_WEEKLY
 			: Lesson::RECURRENCE_SINGLE;
@@ -212,7 +218,7 @@ class BookingEndpoint {
 	private function answers( \WP_REST_Request $request ): array {
 		$out = [];
 		foreach ( (array) $request->get_param( 'answers' ) as $questionId => $value ) {
-			$out[ (int) $questionId ] = sanitize_text_field( (string) $value );
+			$out[ (int) $questionId ] = sanitize_text_field( Val::string( $value ) );
 		}
 
 		return $out;
@@ -220,13 +226,13 @@ class BookingEndpoint {
 
 	private function clientIp(): ?string {
 		// phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized, WordPress.Security.ValidatedSanitizedInput.MissingUnslash -- IP stored verbatim for audit.
-		$ip = sanitize_text_field( wp_unslash( $_SERVER['REMOTE_ADDR'] ?? '' ) );
+		$ip = sanitize_text_field( Val::string( wp_unslash( $_SERVER['REMOTE_ADDR'] ?? '' ) ) );
 
 		return '' !== $ip ? $ip : null;
 	}
 
 	public function updateStatus( \WP_REST_Request $request ): \WP_REST_Response|\WP_Error {
-		$id     = absint( $request->get_param( 'id' ) );
+		$id     = absint( Val::int( $request->get_param( 'id' ) ) );
 		$lesson = $this->bookings->findById( $id );
 
 		if ( null === $lesson ) {
@@ -237,7 +243,7 @@ class BookingEndpoint {
 			return new \WP_Error( 'forbidden', __( 'You cannot update this booking.', 'unsupervised-schedular' ), [ 'status' => 403 ] );
 		}
 
-		$this->bookings->updateStatus( $id, (string) $request->get_param( 'status' ) );
+		$this->bookings->updateStatus( $id, Val::string( $request->get_param( 'status' ) ) );
 
 		return new \WP_REST_Response(
 			[