Add cancellation cutoff limiting how close to a lesson a student can cancel

Students can no longer cancel their own lesson online once it starts within a
configured window; instructors and studio admins can always cancel.

- Studio default `us_cancellation_cutoff_hours` (stored/computed in hours,
  entered and displayed in days under Studio Settings → Cancellations).
- Optional per-offering override `cancellation_cutoff_hours` (entered in hours);
  blank inherits the studio default, 0 allows anytime cancellation.
- `Booking\CancellationPolicy` resolves the effective window and decides;
  `BookingEndpoint::cancel()` returns a 403 `cancellation_closed` when too late.
  The instructor status endpoint and studio-admin student actions bypass it.

Closes #93

Co-Authored-By: Claude Opus 4.8 <[email protected]>

src/Offering/Offering.php

@@ -42,6 +42,7 @@ class Offering {
 		public readonly ?string $termEnd = null,
 		public readonly ?string $scheduleNote = null,
 		public readonly ?string $etransferEmail = null,
+		public readonly ?int $cancellationCutoffHours = null,
 		public readonly bool $isActive = true,
 		public readonly ?int $id = null,
 	) {}
@@ -83,6 +84,7 @@ class Offering {
 			termEnd:         Val::stringOrNull( $row->term_end ),
 			scheduleNote:    Val::stringOrNull( $row->schedule_note ),
 			etransferEmail:  Val::stringOrNull( $row->etransfer_email ),
+			cancellationCutoffHours: Val::intOrNull( $row->cancellation_cutoff_hours ),
 			isActive:        Val::bool( $row->is_active ),
 			id:              Val::int( $row->id ),
 		);
@@ -99,21 +101,22 @@ class Offering {
 	 */
 	public function toArray( bool $includeEtransferEmail = true ): array {
 		$out = [
-			'id'               => $this->id,
-			'instructor_id'    => $this->instructorId,
-			'kind'             => $this->kind,
-			'title'            => $this->title,
-			'description'      => $this->description,
-			'duration_minutes' => $this->durationMinutes,
-			'price'            => $this->price,
-			'currency'         => $this->currency,
-			'billing_mode'     => $this->billingMode,
-			'allow_weekly'     => $this->allowWeekly,
-			'capacity'         => $this->capacity,
-			'term_start'       => $this->termStart,
-			'term_end'         => $this->termEnd,
-			'schedule_note'    => $this->scheduleNote,
-			'is_active'        => $this->isActive,
+			'id'                        => $this->id,
+			'instructor_id'             => $this->instructorId,
+			'kind'                      => $this->kind,
+			'title'                     => $this->title,
+			'description'               => $this->description,
+			'duration_minutes'          => $this->durationMinutes,
+			'price'                     => $this->price,
+			'currency'                  => $this->currency,
+			'billing_mode'              => $this->billingMode,
+			'allow_weekly'              => $this->allowWeekly,
+			'capacity'                  => $this->capacity,
+			'term_start'                => $this->termStart,
+			'term_end'                  => $this->termEnd,
+			'schedule_note'             => $this->scheduleNote,
+			'cancellation_cutoff_hours' => $this->cancellationCutoffHours,
+			'is_active'                 => $this->isActive,
 		];
 
 		if ( $includeEtransferEmail ) {

src/Offering/OfferingController.php

@@ -104,6 +104,11 @@ class OfferingController {
 		$duration = absint( Val::int( $_POST['duration_minutes'] ?? 0 ) );
 		$capacity = absint( Val::int( $_POST['capacity'] ?? 0 ) );
 
+		// A blank cutoff means "use the studio default" (null); any entered value
+		// (including 0 — cancel any time) is a per-offering override.
+		$cutoffRaw   = trim( sanitize_text_field( Val::string( wp_unslash( $_POST['cancellation_cutoff_hours'] ?? '' ) ) ) );
+		$cutoffHours = '' === $cutoffRaw ? null : absint( Val::int( $cutoffRaw ) );
+
 		// Term dates: a class either meets once (term ends the day it starts)
 		// or repeats weekly for a set number of sessions.
 		$termStart = Offering::normalizeDate( sanitize_text_field( Val::string( wp_unslash( $_POST['term_start'] ?? '' ) ) ) );
@@ -129,6 +134,7 @@ class OfferingController {
 			termEnd:         $termEnd,
 			scheduleNote:    $this->nullableText( sanitize_text_field( Val::string( wp_unslash( $_POST['schedule_note'] ?? '' ) ) ) ),
 			etransferEmail:  $this->nullableText( sanitize_email( Val::string( wp_unslash( $_POST['etransfer_email'] ?? '' ) ) ) ),
+			cancellationCutoffHours: $cutoffHours,
 			isActive:        isset( $_POST['is_active'] ),
 			id:              $existing?->id,
 		);

src/Offering/OfferingEndpoint.php

@@ -103,6 +103,7 @@ class OfferingEndpoint {
 			termEnd:         $this->nullableText( $request->get_param( 'term_end' ) ),
 			scheduleNote:    $this->nullableText( $request->get_param( 'schedule_note' ) ),
 			etransferEmail:  $this->nullableEmail( $request->get_param( 'etransfer_email' ) ),
+			cancellationCutoffHours: $this->nullableInt( $request->get_param( 'cancellation_cutoff_hours' ) ),
 			isActive:        null === $request->get_param( 'is_active' ) ? true : (bool) $request->get_param( 'is_active' ),
 		);
 
@@ -148,6 +149,7 @@ class OfferingEndpoint {
 			termEnd:         $request->has_param( 'term_end' ) ? $this->nullableText( $request->get_param( 'term_end' ) ) : $existing->termEnd,
 			scheduleNote:    $request->has_param( 'schedule_note' ) ? $this->nullableText( $request->get_param( 'schedule_note' ) ) : $existing->scheduleNote,
 			etransferEmail:  $request->has_param( 'etransfer_email' ) ? $this->nullableEmail( $request->get_param( 'etransfer_email' ) ) : $existing->etransferEmail,
+			cancellationCutoffHours: $request->has_param( 'cancellation_cutoff_hours' ) ? $this->nullableInt( $request->get_param( 'cancellation_cutoff_hours' ) ) : $existing->cancellationCutoffHours,
 			isActive:        $request->has_param( 'is_active' ) ? (bool) $request->get_param( 'is_active' ) : $existing->isActive,
 			id:              $id,
 		);

src/Offering/OfferingRepository.php

@@ -14,11 +14,12 @@ class OfferingRepository {
 	/**
 	 * Column formats aligned to {@see columns()} (instructor_id, kind, title,
 	 * description, duration_minutes, price, currency, billing_mode, allow_weekly,
-	 * capacity, term_start, term_end, schedule_note, etransfer_email, is_active).
+	 * capacity, term_start, term_end, schedule_note, etransfer_email,
+	 * cancellation_cutoff_hours, is_active).
 	 *
 	 * @var list<string>
 	 */
-	private const COLUMN_FORMATS = [ '%d', '%s', '%s', '%s', '%d', '%f', '%s', '%s', '%d', '%d', '%s', '%s', '%s', '%s', '%d' ];
+	private const COLUMN_FORMATS = [ '%d', '%s', '%s', '%s', '%d', '%f', '%s', '%s', '%d', '%d', '%s', '%s', '%s', '%s', '%d', '%d' ];
 
 	public function insert( Offering $offering ): int {
 		$this->db->insert(
@@ -47,21 +48,22 @@ class OfferingRepository {
 	 */
 	private function columns( Offering $offering ): array {
 		return [
-			'instructor_id'    => $offering->instructorId,
-			'kind'             => $offering->kind,
-			'title'            => $offering->title,
-			'description'      => $offering->description,
-			'duration_minutes' => $offering->durationMinutes,
-			'price'            => $offering->price,
-			'currency'         => $offering->currency,
-			'billing_mode'     => $offering->billingMode,
-			'allow_weekly'     => $offering->allowWeekly ? 1 : 0,
-			'capacity'         => $offering->capacity,
-			'term_start'       => $offering->termStart,
-			'term_end'         => $offering->termEnd,
-			'schedule_note'    => $offering->scheduleNote,
-			'etransfer_email'  => $offering->etransferEmail,
-			'is_active'        => $offering->isActive ? 1 : 0,
+			'instructor_id'             => $offering->instructorId,
+			'kind'                      => $offering->kind,
+			'title'                     => $offering->title,
+			'description'               => $offering->description,
+			'duration_minutes'          => $offering->durationMinutes,
+			'price'                     => $offering->price,
+			'currency'                  => $offering->currency,
+			'billing_mode'              => $offering->billingMode,
+			'allow_weekly'              => $offering->allowWeekly ? 1 : 0,
+			'capacity'                  => $offering->capacity,
+			'term_start'                => $offering->termStart,
+			'term_end'                  => $offering->termEnd,
+			'schedule_note'             => $offering->scheduleNote,
+			'etransfer_email'           => $offering->etransferEmail,
+			'cancellation_cutoff_hours' => $offering->cancellationCutoffHours,
+			'is_active'                 => $offering->isActive ? 1 : 0,
 		];
 	}