feat: install Flysystem S3 and configure SeaweedFS storage

Add league/flysystem-bundle and league/flysystem-aws-s3-v3 packages and
configure the default.storage adapter to use AWS S3Client pointed at the
SeaweedFS endpoint (s3.lclr.dev) with path-style endpoints and secret-based
credentials.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

config/packages/flysystem.yaml

@@ -0,0 +1,19 @@
+flysystem:
+    storages:
+        default.storage:
+            adapter: 'aws'
+            options:
+                client: 's3_client'
+                bucket: 'ltbxd-actorle'
+
+services:
+    s3_client:
+        class: Aws\S3\S3Client
+        arguments:
+            -   endpoint: 'https://s3.lclr.dev'
+                credentials:
+                    key: '%env(secret:S3_ACCESS_KEY)%'
+                    secret: '%env(secret:S3_SECRET_KEY)%'
+                region: 'us-east-1'
+                version: 'latest'
+                use_path_style_endpoint: true