Upload hooks:
- StorageHooks class with fire-and-forget event emitter pattern
- Events: upload, upload:error, delete, delete:error, download
- All StorageClient operations now emit appropriate events
- Unsubscribe functions for cleanup
Metrics:
- StorageMetricsCollector interface (decoupled from prom-client)
- InMemoryMetrics for testing and local dev
- attachMetrics() wires hooks to any collector automatically
- Backends can create a Prometheus collector via MetricsService
Presigned multipart upload (browser direct-upload):
- createMultipartUpload() initiates and returns uploadId
- getMultipartUploadUrls() generates presigned PUT URLs per part
- completeMultipartUpload() finalizes with part ETags
- abortMultipartUpload() for cleanup on abandoned uploads
90 tests passing across 5 test files.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
