Release version 0.13.9

• Improved the new conversation flow so default agents are resolved more reliably across folder defaults, available-agent ordering, restored draft tabs, and retry/new-session entry points.
• Refreshed the welcome panel with a cleaner centered layout, softer background treatment, highlighted greeting text, and a lighter rotating tip area.
• Added a full test pipeline covering frontend lint/Vitest/build plus Rust desktop/server checks across Linux, macOS, and Windows.
• Expanded Rust and frontend coverage with parser snapshots, HTTP/WebSocket integration tests, command core tests, and React component regression tests.
• Consolidated web handlers around shared command core functions so desktop and server entry points exercise the same business logic.
• Updated README, AGENTS, CLAUDE, and translated docs with the new test and verification commands.
• Cleaned up cross-platform Rust warnings and CI edge cases, including Windows desktop test handling and stricter clippy coverage.

发布版本 0.13.9

• 优化新会话的默认代理选择逻辑：文件夹默认代理、可用代理排序、恢复的草稿标签、重试/新会话入口现在会以更稳定的优先级解析。
• 重做欢迎面板体验：布局更集中，背景更轻，标题高亮更清晰，提示区域也更克制。
• 新增完整测试流水线，覆盖前端 lint、Vitest、静态构建，以及 Rust 桌面/服务器模式在 Linux、macOS、Windows 上的检查。
• 扩充测试覆盖：加入解析器快照、HTTP/WebSocket 集成测试、命令核心逻辑测试和多个 React 组件回归测试。
• 将 Web API handler 收敛到共享的 command core 实现，桌面端和服务器端现在走同一套业务逻辑。
• 同步更新 README、AGENTS、CLAUDE 以及多语言文档中的测试与验证命令。
• 清理跨平台 Rust 告警和 CI 边界问题，包括 Windows 桌面测试处理与更严格的 clippy 检查。