csharp/sandbox/v0.1.3

## What's New

### Features

- Added `resourceRequests` to sandbox creation so Kubernetes-backed sandboxes can set resource requests separately from limits. Omitting the field preserves the existing behavior where requests match limits.
- Added line-based file reads through `GET /files/download` with `offset` and `limit` query parameters, enabling C# callers to read large text files by line range.
- Added directory listing support through the new execd directory API. The SDK now exposes depth-controlled traversal and file entry types, while symlinks are reported as symlinks and are not recursively traversed. https://github.com/opensandbox-group/OpenSandbox/pull/1001
- Added detailed replace-content feedback without breaking existing callers. Existing replace methods keep their original behavior, while detailed methods opt in to per-file `replacedCount` results so callers can detect no-match and multi-match replacements. https://github.com/opensandbox-group/OpenSandbox/pull/991
- Added Credential Vault support to the C# SDK surface, including model, adapter, sandbox creation, unit test, and E2E coverage. https://github.com/opensandbox-group/OpenSandbox/pull/1009 https://github.com/opensandbox-group/OpenSandbox/pull/1023

### Bug Fixes

- Directory listing now omits a null depth query parameter, allowing the server-side default depth to apply cleanly.
- Fixed replace-content detailed response handling while keeping the original replace API backward-compatible. https://github.com/opensandbox-group/OpenSandbox/pull/991

### Misc

- Bumped the C# Sandbox SDK package version to `0.1.3`.

### Contributors

- @Pangjiping
- @asiudgufgbukbsa
- @jwx0925
- @ninan-nn