fix: resolve PHPStan errors from merged PRs

- MessageMap (prism-php#971): guard first() against null before
  accessing reasoning properties.
- EnumSchema (prism-php#1024): add value types to options() docblock.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: wishborn

src/Providers/OpenAI/Maps/MessageMap.php

@@ -122,8 +122,9 @@ protected function mapAssistantMessage(AssistantMessage $message): void
                 ->groupBy(fn (ToolCall $toolCall): string => $toolCall->reasoningId ?? '');
 
             foreach ($grouped as $reasoningId => $toolCalls) {
-                if ($reasoningId !== '') {
-                    $first = $toolCalls->first();
+                $first = $toolCalls->first();
+
+                if ($reasoningId !== '' && $first instanceof ToolCall) {
                     $this->mappedMessages[] = [
                         'type' => 'reasoning',
                         'id' => $first->reasoningId,

src/Schema/EnumSchema.php

@@ -34,6 +34,9 @@ public function toArray(): array
         ];
     }
 
+    /**
+     * @return array<int, string|int|float|null>
+     */
     protected function options(): array
     {
         $options = $this->options;