docs(changelog): add April 26-27 changelogs (EN/CN)

- Public-facing changelogs covering AI built-in skills, security, and bug fixes
- English and Chinese versions for each date
- Author: ZhenYi

changelog/2026-04-26-cn.mdx

@@ -0,0 +1,26 @@
+---
+date: 2026-04-26
+title: "更新日志 — 2026年4月26日"
+lang: cn
+author: ZhenYi
+---
+
+## AI 智能体改进
+
+- **更智能的上下文感知**：AI 现在在你 @提及仓库时自动理解仓库上下文，包含名称、描述和默认分支等信息。
+- **实时事件推送**：新增 WebSocket 事件支持，当 AI 配置变更或仓库创建、重命名、删除时，界面实时同步更新。
+- **修复模型同步问题**：解决了上游模型同步 URL 路径重复的问题。
+
+## 前端
+
+- **更好的自动补全**：@提及建议现在显示仓库类型，方便快速定位目标仓库。
+- **连接恢复能力**：WebSocket token 在断连后自动刷新，AI 和实时功能平滑恢复。
+
+## 可观测性
+
+- **人性化日志**：终端会话现在使用可读的日志格式，服务器环境仍保留 JSON 格式。
+
+## 性能与稳定性
+
+- **内存泄漏修复**：解决了聊天服务中的两个内存泄漏问题。
+- **缓存优化**：聊天和工作空间缓存在相关事件发生时正确刷新。

changelog/2026-04-26-en.mdx

@@ -0,0 +1,26 @@
+---
+date: 2026-04-26
+title: "Changelog — April 26, 2026"
+lang: en
+author: ZhenYi
+---
+
+## AI Agent Improvements
+
+- **Smarter context**: AI now automatically understands which repository you're talking about when you @mention it, with full context including description and default branch.
+- **Real-time updates**: New WebSocket events keep the UI in sync when AI configs change or repositories are created, renamed, or deleted.
+- **Fixed model sync**: Resolved an issue where the upstream model sync URL would contain a duplicate path segment.
+
+## Frontend
+
+- **Better autocomplete**: @mention suggestions now show the repository type, making it easier to find the right repo.
+- **Connection resilience**: WebSocket token now auto-refreshes after disconnection, so AI and real-time features recover smoothly.
+
+## Observability
+
+- **Human-friendly logs**: Terminal sessions now use readable log formatting. JSON format is preserved for server environments.
+
+## Performance & Stability
+
+- **Memory leak fixes**: Resolved two memory leaks in the room service.
+- **Cache improvements**: Room and workspace caches now properly refresh on relevant events.

changelog/2026-04-27-cn.mdx

@@ -0,0 +1,60 @@
+---
+date: 2026-04-27
+title: "更新日志 — 2026年4月27日"
+lang: cn
+author: ZhenYi
+---
+
+## AI 智能体 — 内置技能系统
+
+正式推出内置技能系统，共 16 个预置技能，AI 可根据对话上下文自动匹配并激活：
+
+**Git 操作**
+- 提交历史分析 — 查看项目演进、搜索特定提交、展示分支图谱
+- 代码变更分析 — 对比提交差异、统计变更规模、追溯代码来源
+- 分支管理 — 查看分支列表、检测合并状态、分析分支同步情况
+
+**代码质量**
+- 代码审查 — 涵盖安全漏洞、性能问题、代码规范的专业审查
+- 代码解读 — 用通俗易懂的方式解释复杂代码逻辑
+
+**项目管理**
+- 仓库管理 — 浏览、创建和配置项目仓库
+- 议题管理 — 分类、贴上标签、评定优先级的完整议题管理
+- 看板管理 — 组织看板、管理任务卡片、跟踪工作进度
+- 成员管理 — 查看团队组成、管理角色权限
+
+**开发效率**
+- PR 摘要 — 自动生成简洁清晰的 PR 描述
+- 议题分类 — 智能评定议题类型、优先级和所属模块
+- 文档生成 — 生成 README、API 文档和代码注释
+- 测试生成 — 为代码编写规范的单元测试
+- 提交信息生成 — 自动生成符合规范的提交信息
+
+**实用工具**
+- HTTP 请求 — 进行 API 测试和调试
+
+所有内置技能默认对所有项目可用，用户可直接通过 @技能名 或自然语言激活，也可在项目设置中自定义覆盖。
+
+## AI — 模型同步
+
+- 新增模型"离线"状态，每次同步自动更新在线状态
+- 基于模型名称自动去重，避免重复记录（跨服务商）
+- 同步周期为每 10 分钟，确保模型信息实时准确
+
+## 安全加固
+
+- LFS 认证机制现在严格验证 token 有效性，包含撤销状态和过期时间检查
+- 会话密钥由 SHA-256 升级至 SHA-512，增强加密强度
+- 敏感 token 不再出现在生产日志中
+
+## 问题修复
+
+- 修复提交历史页面时间显示错误
+- 修复加载状态下仓库信息字段不匹配导致的页面异常
+- 修复聊天室删除时相关数据未完全清理的问题
+- 修复音频录制异常时资源未正确释放的问题
+- 修复 WebSocket 连接关闭时待处理请求可能丢失的问题
+- 修复 AI 账单记录失败时静默丢失错误的问题
+- 修复仓库列表在大量提交时的 N+1 查询性能问题
+- 提升各模块稳定性，移除多处潜在的运行时崩溃风险

changelog/2026-04-27-en.mdx

@@ -0,0 +1,60 @@
+---
+date: 2026-04-27
+title: "Changelog — April 27, 2026"
+lang: en
+author: ZhenYi
+---
+
+## AI Agent — Built-in Skills System
+
+We've launched a built-in skills system with 16 pre-configured skills. The AI automatically matches and activates the right skill based on conversation context:
+
+**Git Operations**
+- Commit history analysis — view project evolution, search commits, visualize branch graphs
+- Code change analysis — compare diffs, summarize changes, trace code authorship
+- Branch management — list branches, check merge status, analyze sync state
+
+**Code Quality**
+- Code review — professional review covering security, performance, and best practices
+- Code explainer — clarify complex code in plain language
+
+**Project Management**
+- Repository management — browse, create, and configure project repos
+- Issue management — full workflow with triage, labels, and priority assessment
+- Board management — organize kanban boards, manage cards, track progress
+- Member management — view team structure, manage roles and permissions
+
+**Developer Productivity**
+- PR summary — auto-generate clear and concise PR descriptions
+- Issue triage — intelligently classify issue type, priority, and component
+- Documentation generator — create README, API docs, and inline docs
+- Test generator — write well-structured unit tests
+- Commit message generator — auto-generate conventional commit messages
+
+**Utility**
+- HTTP requester — API testing and debugging
+
+All built-in skills are available to every project by default. Use `@skill-name` or natural language to activate them. Project admins can customize or override them.
+
+## AI — Model Sync
+
+- New "offline" model status — sync now tracks which models are actually available
+- Automatic deduplication by model name (regardless of provider)
+- Syncs every 10 minutes to keep model info accurate
+
+## Security
+
+- LFS authentication now validates tokens against revocation and expiry
+- Session encryption upgraded from SHA-256 to SHA-512
+- Sensitive tokens no longer appear in production logs
+
+## Bug Fixes
+
+- Fixed incorrect timestamps on the commit history page
+- Fixed repository info display errors during page loading
+- Fixed incomplete data cleanup when deleting chat rooms
+- Fixed audio resources not being released on recording errors
+- Fixed pending requests potentially lost on WebSocket disconnect
+- Fixed AI billing errors being silently dropped
+- Fixed query performance issue when listing repositories with many commits
+- Improved overall stability by removing multiple potential runtime crashes