P2: S3 Multipart Upload support complete

- InitiateMultipartUpload: POST /s3/multipart/:bucket/:key/init
- UploadPart: PUT /s3/multipart/:bucket/:key/part
- CompleteMultipartUpload: POST /s3/multipart/:bucket/:key/complete
- AbortMultipartUpload: DELETE /s3/multipart/:bucket/:key/abort
- In-memory upload tracking with once_cell::Lazy
- Part files stored in temp dir during upload
- Final file assembled on CompleteMultipartUpload
- XML responses for all operations

Tests: 293 passed, 0 failed

markbase-core/Cargo.toml

@@ -20,6 +20,8 @@ axum = { version = "0.7", features = ["macros"] }
 bcrypt = "0.16"
 bytes = "1"
 chrono = { version = "0.4", features = ["serde"] }
+lazy_static = "1.5"
+once_cell = "1.21"
 regex = "1"
 clap = { version = "4", features = ["derive"] }
 dav-server = "0.11"