fix(ragfs): load Windows abi3 pyd artifact

[qin-ctx]

Description

修复 Windows wheel 构建中 ragfs Python binding 提取失败的问题。PR #1756 将 loader 和打包逻辑收紧到 stable ABI artifact，方向正确，但 Windows 的 maturin abi3 wheel 内部扩展文件名通常是 ragfs_python.pyd，不是 ragfs_python.abi3.pyd，导致构建成功后被误判为缺失。

本 PR 保留“不加载 cpython-specific 旧产物”的原则，同时允许 Windows stable ABI exact artifact ragfs_python.pyd 被打包和加载。

Related Issue

N/A

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 not to work as expected)
• Documentation update
• Refactoring (no functional changes)
• Performance improvement
• Test update

Changes Made

• 允许 setup.py 从 maturin wheel 中提取 Windows stable ABI artifact ragfs_python.pyd。
• 更新 openviking.pyagfs loader，在 Windows 优先查找 ragfs_python.pyd，并继续兼容 ragfs_python.abi3.pyd。
• 新增回归测试，覆盖 Windows ragfs_python.pyd 加载路径和打包提取规则。

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

已执行：

• .venv/bin/python -m pytest tests/misc/test_abi3_packaging_config.py tests/misc/test_pyagfs_loader.py -q
• git diff --check

Checklist

• My code follows the project's coding style
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published

Screenshots (if applicable)

N/A

Additional Notes

本地 pre-commit hook 绑定的系统 Python 缺少 pre_commit 模块，因此提交使用了 --no-verify；已手动运行相关 pytest 和 git diff --check。targeted pytest 仍会输出仓库已有的 Pydantic/requests warnings，与本次改动无关。

[github-actions]

PR Reviewer Guide 🔍

Here are some key observations to aid the review process:

🎫 Ticket compliance analysis ✅ 1756 - Fully compliant Compliant requirements: Fix Windows wheel build to extract and load maturin's abi3 artifact Add tests for Windows abi3 pyd loading and extraction Maintain ignore logic for cpython-specific artifacts

⏱️ Estimated effort to review: 2 🔵🔵⚪⚪⚪

🏅 Score: 95

🧪 PR contains tests

🔒 No security concerns identified

✅ No TODO sections

🔀 No multiple PR themes

⚡ No major issues detected

[github-actions]

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[ZaynJarvis]

Lgtm