chore: major code cleanup and type safety using phpstan

src/BusProNet/DataProcessor/ServiceMappingCollector.php

@@ -43,7 +43,7 @@ class ServiceMappingCollector
      * Groups board, ski passes, rentals, rental insurance, courses, parking, and additional services
      * by service ID with their participant assignments (1-based).
      *
-     * @return array<string, array<int>> Map of service ID to participant IDs
+     * @return array<int, list<int>> Map of service ID to participant IDs
      */
     public function collectServiceMappings(BookingDto $bookingDto): array
     {
@@ -99,7 +99,7 @@ class ServiceMappingCollector
     /**
      * Collects transportation service mappings.
      *
-     * @return array<string, array<int>> Map of transportation service ID to participant IDs
+     * @return array<int, list<int>> Map of transportation service ID to participant IDs
      */
     public function collectTransportationMappings(BookingDto $bookingDto): array
     {
@@ -126,7 +126,7 @@ class ServiceMappingCollector
      * Collects the unified pickup selection which applies to both directions.
      * The API receives this as outbound pickup data.
      *
-     * @return array<string, array<int>> Map of pickup ID to participant IDs
+     * @return array<int, list<int>> Map of pickup ID to participant IDs
      */
     public function collectPickupMappings(BookingDto $bookingDto): array
     {
@@ -148,7 +148,7 @@ class ServiceMappingCollector
      *
      * Collects the drop-off selection for the inbound/return direction.
      *
-     * @return array<string, array<int>> Map of drop-off ID to participant IDs
+     * @return array<int, list<int>> Map of drop-off ID to participant IDs
      */
     public function collectDropOffMappings(BookingDto $bookingDto): array
     {
@@ -171,7 +171,7 @@ class ServiceMappingCollector
      * CRITICAL: Insurance data is only included in CREATE flow, not in UPDATE flow.
      * IMPORTANT: Excludes synthetic "no insurance" option from BPN transmission.
      *
-     * @return array<string, array<int>> Map of insurance ID to participant IDs
+     * @return array<string, list<int>> Map of insurance ID to participant IDs
      */
     public function collectInsuranceMappings(BookingDto $bookingDto): array
     {