feat(drivers/139): merge multiple share roots

[syscc]

Summary / 摘要

• Support multiple 139 share link ids in share mode.

• Support password form link_id#password.

• Merge multiple share roots into one root listing instead of showing raw share ids.

• Keep preview and download behavior as 302 redirects.

• Add regression tests for multi-share parsing and reference encoding.

• This PR has breaking changes.
  / 此 PR 包含破坏性变更。

• This PR changes public API, config, storage format, or migration behavior.
  / 此 PR 修改了公开 API、配置、存储格式或迁移行为。

• This PR requires corresponding changes in related repositories.
  / 此 PR 需要关联仓库同步修改。

Related repository PRs / 关联仓库 PR:

• OpenList-Frontend:
• OpenList-Docs: docs(drivers): update 139yun document OpenList-Docs#346

Related Issues / 关联 Issue

N/A

Testing / 测试

• GOTOOLCHAIN=local go test ./drivers/139
• Manual test / 手动测试: verified merged share root listing and direct 302 preview/download behavior in source-mode local run

Checklist / 检查清单

• I have read CONTRIBUTING.
  / 我已阅读 CONTRIBUTING。
• I confirm this contribution follows the repository license, contribution policy, and code of conduct.
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• I have formatted the changed code with gofmt, go fmt, or prettier where applicable.
  / 我已按适用情况使用 gofmt、go fmt 或 prettier 格式化变更代码。
• I have requested review from relevant maintainers or code owners where applicable.
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AI Disclosure / AI 使用声明

• This PR includes AI-assisted content.
  / 此 PR 包含 AI 辅助内容。

Tools used / 使用工具:

• Codex

Usage scope / 使用范围:

• Code generation / 代码生成

• Refactoring / 重构

• Tests / 测试

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• I have reviewed and validated all AI-assisted content included in this PR.
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• I can reproduce all AI-assisted content included in this PR without any AI tools.
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[syscc]

Updated the PR with a no-account fallback for 139 share links: when original download requires account authentication but the share API provides a preview URL, the driver now returns the preview URL so video playback can still work without cookies. Original file download still requires account authentication.