fix: Add IDropboxMaterializerApi to provides(), restrict retries to GET

- Register in deferred provider's provides() so DI resolution works
- Limit GuzzleRetryMiddleware to GET requests only (POST endpoints are
  idempotent but no reason to retry them on 429/503)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: caseylocker

app/Services/Apis/DropboxMaterializerApi.php

@@ -37,7 +37,9 @@ final class DropboxMaterializerApi implements IDropboxMaterializerApi
     public function __construct()
     {
         $stack = HandlerStack::create();
-        $stack->push(GuzzleRetryMiddleware::factory());
+        $stack->push(GuzzleRetryMiddleware::factory([
+            'retry_on_methods' => ['GET'],
+        ]));
 
         $this->client = new Client([
             'handler'         => $stack,

app/Services/BaseServicesProvider.php

@@ -199,6 +199,7 @@ public function provides()
             IPushNotificationApi::class,
             IGeoCodingAPI::class,
             IExternalUserApi::class,
+            IDropboxMaterializerApi::class,
             IFolderService::class,
             ILockManagerService::class,
             IPasswordlessAPI::class,