* fix(storage): support custom S3 endpoints for self-hosted deployments
When AWS_ENDPOINT_URL is set, the S3 client now uses path-style
addressing and routes requests to the custom endpoint (e.g. MinIO).
Returns path-style URLs (endpoint/bucket/key) instead of virtual-hosted
URLs so attachments are accessible on local setups.
Also falls back to STANDARD storage class for custom endpoints since
MinIO and other S3-compatible stores do not support INTELLIGENT_TIERING.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
* fix(storage): handle custom endpoint URLs in KeyFromURL
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Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
