feat: extensible participant status determination for booking creation

Adds a rule-based system to determine participant status in CREATE
payloads. Participants selecting a 'Begleitperson' service now receive
status 'O' (Option), all others default to 'F' (Final).

- Add ParticipantStatusRuleInterface for defining status rules
- Add ParticipantStatusRuleRegistry for priority-based rule evaluation
- Add ChaperonServiceStatusRule for Begleitperson detection
- Integrate status evaluation into BookingPayloadBuilder

src/BusProNet/Service/Contract/ParticipantStatusRuleInterface.php

@@ -0,0 +1,52 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\BusProNet\Service\Contract;
+
+use App\Form\Model\ParticipantDto;
+
+/**
+ * Defines the contract for participant status evaluation rules.
+ *
+ * Status rules are evaluated in priority order to determine the appropriate
+ * status code for a participant during booking creation. The first rule that
+ * matches (evaluate returns true) determines the participant's status.
+ */
+interface ParticipantStatusRuleInterface
+{
+    /**
+     * Evaluates whether this rule applies to the given participant.
+     *
+     * @param ParticipantDto $participant The participant to evaluate
+     *
+     * @return bool True if this rule applies, false otherwise
+     */
+    public function evaluate(ParticipantDto $participant): bool;
+
+    /**
+     * Returns the status code to assign when this rule matches.
+     *
+     * @return string The status code (e.g., 'O' for Option, 'F' for Final)
+     */
+    public function getStatus(): string;
+
+    /**
+     * Returns the priority of this rule.
+     *
+     * Higher priority rules are evaluated first. Rules with the same priority
+     * are evaluated in registration order.
+     *
+     * @return int The priority value (higher = evaluated first)
+     */
+    public function getPriority(): int;
+
+    /**
+     * Returns a human-readable description of this rule.
+     *
+     * Used for debugging and logging purposes.
+     *
+     * @return string Description of what this rule checks
+     */
+    public function getDescription(): string;
+}