* Fix S3 conditional writes with versioning (Issue #8073)
Refactors conditional header checks to properly resolve the latest object version when versioning is enabled. This prevents incorrect validation against non-versioned root objects.
* Add integration test for S3 conditional writes with versioning (Issue #8073)
* Refactor: Propagate internal errors in conditional header checks
- Make resolveObjectEntry return errors from isVersioningConfigured
- Update checkConditionalHeaders checks to return 500 on internal resolve errors
* Refactor: Stricter error handling and test assertions
- Propagate internal errors in checkConditionalHeaders*WithGetter functions
- Enforce strict 412 PreconditionFailed check in integration test
* Perf: Add early return for conditional headers + safety improvements
- Add fast path to skip resolveObjectEntry when no conditional headers present
- Avoids expensive getLatestObjectVersion retries in common case
- Add nil checks before dereferencing pointers in integration test
- Fix grammar in test comments
- Remove duplicate comment in resolveObjectEntry
* Refactor: Use errors.Is for robust ErrNotFound checking
- Update checkConditionalHeaders* to use errors.Is(err, filer_pb.ErrNotFound)
- Update resolveObjectEntry to use errors.Is for wrapped error compatibility
- Remove duplicate comment lines in s3api handlers
* Perf: Optimize resolveObjectEntry for conditional checks
- Refactor getLatestObjectVersion to doGetLatestObjectVersion supporting variable retries
- Use 1-retry path in resolveObjectEntry to avoid exponential backoff latency
* Test: Enhance integration test with content verification
- Verify actual object content equals expected content after successful conditional write
- Add missing io and errors imports to test file
* Refactor: Final refinements based on feedback
- Optimize header validation by passing parsed headers to avoid redundant parsing
- Simplify integration test assertions using require.Error and assert.True
- Fix build errors in s3api handler and test imports
* Test: Use smithy.APIError for robust error code checking
- Replace string-based error checking with structured API error
- Add smithy-go import for AWS SDK v2 error handling
* Test: Use types.PreconditionFailed and handle io.ReadAll error
- Replace smithy.APIError with more specific types.PreconditionFailed
- Add proper error handling for io.ReadAll in content verification
* Refactor: Use combined error checking and add nil guards
- Use smithy.APIError with ErrorCode() for robust error checking
- Add nil guards for entry.Attributes before accessing Mtime
- Prevents potential panics when Attributes is uninitialized
