Add comprehensive Chinese FAQ for common credential errors and configuration issues

[Copilot]

Created a detailed FAQ document (FAQ-CN.md) addressing common credential-related errors based on source code analysis and existing GitHub issues.

Coverage

19 questions across 8 categories:

• Environment variables (ALIBABA_CLOUD_ACCESS_KEY_ID case sensitivity, empty values)
• Credential types (invalid type errors, Bearer token requirements)
• ECS RAM roles (STS token refresh failures, IMDSv2 metadata issues)
• Configuration files (path validation, profile selection, required fields)
• Network/timeouts (connection timeouts, proxy configuration)
• Version compatibility (Go 1.25 syscall.Flock compilation errors - Issue go 1.25.3版本这部分是有问题的 #138)
• OIDC credentials (token file paths, session expiration)
• RAM role assumption (session duration limits, AssumeRole failures)

Structure

Each FAQ entry includes:

• Problem description with actual error messages
• Root cause analysis
• Actionable solutions with code examples
• Links to related issues where applicable

Additional sections:

• Best practices for dev/prod environments
• Security recommendations (IMDSv2, credential rotation, least privilege)
• Performance optimization tips
• Credential chain priority order

Integration

Added FAQ links to both README.md and README-CN.md for discoverability.

Example Entry

### Q12: Go 1.25 版本编译失败 - syscall.Flock 问题

**问题描述：** Windows 平台编译失败，报错 `syscall.Flock` 不可用。

**原因分析：** v1.4.8 引入文件锁使用 `syscall.Flock`，Windows 不支持该函数。

**解决方案：**
1. 升级到 v1.4.9+（已使用条件编译修复）
2. 临时降级到 v1.4.7

**相关 Issue：** #138, #141

Original prompt

根据这个项目的源码， 帮我分析出出错的case，然后整理成中文的faq，也可以参考项目已经存在的issue，整体存在的issue和解决方案。每个faq的标题应该包含关键信息，答案应该简洁但表达直接。

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