feat: add file-backed canvas notes

Magic Notes previously supported rich-text records without a paged drawing or
PDF annotation workflow. Add the integrated PeopleLib Fabric and Quill editor
with flowing text, pen/highlighter, object transforms, images, paper templates,
PDF backgrounds with native text extraction, and raster PDF export. Saves are
manual; undo/redo remains scoped to an annotation page or Quill mode.

Analyze drafts, saved canvases and canvas-source todos with page images and
text when the default model supports images, or an explicitly labelled
text-only fallback. Keep successful saves when automatic analysis fails and
prevent MCP plain-text replacement of canvas records.

Move entry bodies and binary assets into local note files with schema 38
migration and verified readback. SQLite retains metadata, indexes, revisions,
todos and comments. Backups must coordinate SQLite and the adjacent notes
directory while writes are paused or the app is closed; no one-click backup
action is included.

Show a continuous record stream with independent collapsible record index and
AI pane, real first-page thumbnails, and scroll-only record navigation. Open a
blank text/canvas composer by default and reset it after creation. Protect
unsaved drafts and establish normalized editor baselines after saving so clean
records do not prompt again when leaving.

Validation: latest recorded focused run passed 149 tests across five files;
typecheck, lint and git diff --check passed. The prior user-reported full run
passed 4,713 tests before later corrections and UI changes; it is not a full
validation of this final snapshot. Tests were not rerun for this commit, as
requested; independent systematic review follows the commit.

Release note: Create paged notes with handwriting, flowing text and PDF
annotations, browse records through thumbnails, and request AI comments with
an explicit text-only fallback. Existing notes migrate to local file storage;
backups now need both the database and notes directory.

README.zh-CN.md

@@ -38,7 +38,7 @@ GoodBuddy 是用于模型对话、编程 Agent、知识检索、笔记和定时
 | 范围 | GoodBuddy 提供的能力 |
 | --- | --- |
 | Agent Runtime | 直连模型、OpenCode、Continue 和预览版 DeepSeek Harness |
-| 数据与执行 | 本地 SQLite、只读 `Ask`、使用当前账号完整权限的 `Execute`、工具调用记录 |
+| 数据与执行 | 本地 SQLite 与笔记文件存储、只读 `Ask`、使用当前账号完整权限的 `Execute`、工具调用记录 |
 | 知识库 | 导入文件、目录和网页，通过全文、中文词组、向量和知识图谱检索 |
 | 桌面版本 | Windows、macOS、Linux 的 `x64` 与 `arm64` 正式版本，以及龙芯 LoongArch 实验预览版 |
 | 外部连接 | 本机或内网模型服务、自定义 MCP、微信 ClawBot、企业微信和钉钉 |
@@ -53,6 +53,12 @@ GoodBuddy 是用于模型对话、编程 Agent、知识检索、笔记和定时
 
 ### 魔法笔记与智能心跳
 
+魔法笔记连续展示全部记录，左侧窄栏索引与右侧 AI 评论可独立收起，点击缩略图滚动定位并保留草稿。
+支持富文本记录和分页画布，可混排跨页正文、手写笔迹、高亮、图片与 PDF 底版，
+导入 PDF 时提取原生文字，并将批注页面导出为栅格 PDF。画布由用户手动保存；AI 评论按
+默认模型的图像输入能力分析，不支持图像时明确提示仅文字降级。具体行为与最终验证状态见
+[魔法笔记文档](./docs/features/magic-notes/README.md)。
+
 ![GoodBuddy 魔法笔记](./docs/screenshots/GoodBuddy_MFSGeK0NoT.gif)
 
 ![GoodBuddy 智能心跳](./docs/screenshots/smart-heartbeat.png)