Squashed commit of the following:

commit 0d624137c2557c6eeb87020749e4977b821c2b5c
Author: Adrien <adrien.cesaro@proton.me>
Date:   Thu Apr 9 11:55:22 2026 +0200

    backend native image setup

backend/src/main/resources/application.yaml

@@ -27,7 +27,7 @@ spring:
         index-type: HNSW
         initialize-schema: false
     openai:
-      api-key: ${OPENAI_API_KEY}
+      api-key: ${OPENAI_API_KEY:}
       chat:
         options:
           model: gpt-4o-mini
@@ -62,8 +62,8 @@ app:
     endpoint: https://s3.immich-ad.ovh
     region: garage
     bucket: ${S3_BUCKET:aiteacher}
-    access-key-id: ${S3_ACCESS_KEY_ID}
-    secret-access-key: ${S3_SECRET_ACCESS_KEY}
+    access-key-id: ${S3_ACCESS_KEY_ID:}
+    secret-access-key: ${S3_SECRET_ACCESS_KEY:}
     min-image-size-px: 100
   embedding:
     batch-size: 20