修复完整会话历史与长气泡交互并更新 CentOS 7 发布包

提交当前工作区全部源码、回归脚本、任务记录及重新构建的 Bun baseline 发布包。发布单文件 MCP 初始化及前端资源一致性验证通过。

.trellis/tasks/10-10-mermaid-png-download/task.json

@@ -0,0 +1,26 @@
+{
+  "id": "mermaid-png-download",
+  "name": "mermaid-png-download",
+  "title": "Mermaid 下载默认 2 倍 PNG 图片",
+  "description": "气泡 Mermaid 下载 PNG 图片，默认宽高为图表固有尺寸的 2 倍。",
+  "status": "completed",
+  "dev_type": "frontend",
+  "scope": "mermaid-export",
+  "package": null,
+  "priority": "P2",
+  "creator": "shiyue",
+  "assignee": "shiyue",
+  "createdAt": "2026-10-10",
+  "completedAt": "2026-10-10",
+  "branch": null,
+  "base_branch": "main",
+  "worktree_path": null,
+  "commit": null,
+  "pr_url": null,
+  "subtasks": [],
+  "children": [],
+  "parent": null,
+  "relatedFiles": ["public/app.js"],
+  "notes": "PNG 下载默认 2 倍；Firefox 156.0 验证流程图、时序图、中文换行标签，格式与尺寸通过；语法和差异空白检查通过。",
+  "meta": {}
+}