fix(documents) : add serialization groups to prevent OOM on collection endpoint

The path field (base64 data URIs) is now excluded from GetCollection
via document:list group. Individual GET returns path via document:detail
group. Related entities expose id+name in document:list for attachment
display. Frontend lazy-loads path on download/preview click.

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

src/Entity/Product.php

@@ -30,11 +30,11 @@ class Product
 {
     #[ORM\Id]
     #[ORM\Column(type: Types::STRING, length: 36)]
-    #[Groups(['product:read'])]
+    #[Groups(['product:read', 'document:list'])]
     private ?string $id = null;
 
     #[ORM\Column(type: Types::STRING, length: 255, unique: true)]
-    #[Groups(['product:read'])]
+    #[Groups(['product:read', 'document:list'])]
     private string $name;
 
     #[ORM\Column(type: Types::STRING, length: 255, nullable: true)]