feat(s3): add aliyun oss vendor support and config

[baojun-zhang]

Description

Add s3_vendor to S3FS.

This lets Alibaba Cloud OSS use its supported create-if-absent header.
It also avoids sending unsupported PutObject If-Match headers.

Human Involvement

• A human participated in the implementation or review loop
• This PR was generated entirely by AI agents without human participation in the loop

Related Issue

Fixes #4204

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Refactoring (no functional changes)
• Performance improvement
• Test update

Changes Made

• Add storage.agfs.s3.s3_vendor with standard and aliyun_oss.
• Pass s3_vendor from Python config into the Rust S3FS plugin.
• Add S3FS adapters for If-None-Match and If-Match handling.
• Use x-oss-forbid-overwrite: true for OSS create-if-absent writes.
• Skip PutObject If-Match for OSS overwrite writes and log that CAS is not guaranteed.
• Update Chinese and English S3 configuration docs.

Testing

• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have tested this on the following platforms:
  • Linux
  • macOS
  • Windows

Screenshots (if applicable)