test: add real AWS SDK v3 S3 compatibility tests (20 tests)

Tests use @aws-sdk/client-s3 against https://upload.asepharyana.my.id
with forcePathStyle=true. Covers all standard S3 operations:
ListBuckets, CreateBucket, HeadBucket, DeleteBucket, PutObject,
GetObject, HeadObject, ListObjectsV1/V2 (prefix, delimiter),
CopyObject, DeleteObject, DeleteObjects (batch), error handling.

Multipart is excluded from SDK tests — the SDK adds amz-sdk-* /
x-amz-user-agent to signed headers, which can differ between
signing time and the actual request through Cloudflare, causing
403 SignatureDoesNotMatch. Multipart is verified via manual
SigV4 signing in test/production-e2e.test.ts.

package.json

@@ -27,6 +27,7 @@
     "winston": "^3.11.0"
   },
   "devDependencies": {
+    "@aws-sdk/client-s3": "^3.1079.0",
     "@biomejs/biome": "^2.4.15",
     "@types/node": "^25.8.0",
     "drizzle-kit": "^0.31.10",