fix(os-skills): update dashscope proxy url to new anthropic endpoint

[Ziqi002]

Description

• 更新 DashScope 代理 URL，从已废弃的 /api/v2/apps/claude-code-proxy 切换到新的 /apps/anthropic 端点

SKILL.md 文档和 install-claude-code.sh 安装脚本中的 ANTHROPIC_BASE_URL 都指向了旧的代理路径，
导致新用户按文档配置后无法正常连接。统一更新为新端点。

Related Issue

closes #805

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 change)
• Performance improvement
• CI/CD or build changes

Scope

• cosh (copilot-shell)
• sec-core (agent-sec-core)
• skill (os-skills)
• sight (agentsight)
• tokenless (tokenless)
• memory (agent-memory)
• ckpt (ws-ckpt)
• Multiple / Project-wide

Checklist

• I have read the Contributing Guide
• My code follows the project's code style
• I have added tests that prove my fix is effective or that my feature works
• I have updated the documentation accordingly
• For cosh: Lint passes, type check passes, and tests pass
• For sec-core (Rust): cargo clippy -- -D warnings and cargo fmt --check pass
• For sec-core (Python): Ruff format and pytest pass
• For skill: Skill directory structure is valid and shell scripts pass syntax check
• For sight: cargo clippy -- -D warnings and cargo fmt --check pass
• For tokenless: cargo clippy -- -D warnings and cargo fmt --check pass
• For memory (Linux only): cargo clippy --all-targets -- -D warnings, cargo fmt --check, and cargo test pass
• Lock files are up to date (package-lock.json / Cargo.lock)

Testing

手动安装 Claude Code 并配置新的 DashScope 代理 URL，测试可以正常使用。

Additional Notes