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/Registration/Answer.php

@@ -3,6 +3,8 @@ declare(strict_types=1);
 
 namespace Unsupervised\Schedular\Registration;
 
+use Unsupervised\Schedular\Val;
+
 class Answer {
 
 	public const REG_LESSON     = 'lesson';
@@ -24,14 +26,14 @@ class Answer {
 		public readonly ?int $id = null,
 	) {}
 
-	public static function fromRow( object $row ): self {
+	public static function fromRow( \stdClass $row ): self {
 		return new self(
-			questionId:       (int) $row->question_id,
-			registrationType: $row->registration_type,
-			registrationId:   (int) $row->registration_id,
-			studentId:        (int) $row->student_id,
-			answerValue:      $row->answer_value,
-			id:               (int) $row->id,
+			questionId:       Val::int( $row->question_id ),
+			registrationType: Val::string( $row->registration_type ),
+			registrationId:   Val::int( $row->registration_id ),
+			studentId:        Val::int( $row->student_id ),
+			answerValue:      Val::stringOrNull( $row->answer_value ),
+			id:               Val::int( $row->id ),
 		);
 	}