Fix Chat bridge component dependencies

Use Chat RuntimeException instead of Agent RuntimeException
in Cache\Store and HttpFoundation\SessionStore.

Author: OskarStark

src/chat/src/Bridge/Cache/Store.php

@@ -12,7 +12,7 @@
 namespace Symfony\AI\Chat\Bridge\Cache;
 
 use Psr\Cache\CacheItemPoolInterface;
-use Symfony\AI\Agent\Exception\RuntimeException;
+use Symfony\AI\Chat\Exception\RuntimeException;
 use Symfony\AI\Chat\ManagedStoreInterface;
 use Symfony\AI\Chat\MessageStoreInterface;
 use Symfony\AI\Platform\Message\MessageBag;

src/chat/src/Bridge/HttpFoundation/SessionStore.php

@@ -11,7 +11,7 @@
 
 namespace Symfony\AI\Chat\Bridge\HttpFoundation;
 
-use Symfony\AI\Agent\Exception\RuntimeException;
+use Symfony\AI\Chat\Exception\RuntimeException;
 use Symfony\AI\Chat\ManagedStoreInterface;
 use Symfony\AI\Chat\MessageStoreInterface;
 use Symfony\AI\Platform\Message\MessageBag;