fix: enable undo/redo in notes editor

package.json

@@ -16,6 +16,7 @@
   },
   "license": "MIT",
   "dependencies": {
+    "@codemirror/commands": "6.10.2",
     "@codemirror/lang-markdown": "^6.5.0",
     "@codemirror/language": "^6.12.2",
     "@codemirror/state": "^6.5.2",
@@ -31,6 +32,11 @@
     "@xterm/xterm": "^6.0.0",
     "mermaid": "^11.13.0"
   },
+  "pnpm": {
+    "overrides": {
+      "@codemirror/state": "6.5.4"
+    }
+  },
   "devDependencies": {
     "@playwright/test": "^1.58.2",
     "@sveltejs/vite-plugin-svelte": "^5.0.0",

src/lib/CodeMirrorNoteEditor.svelte

@@ -2,6 +2,7 @@
   import { untrack } from "svelte";
   import { EditorState } from "@codemirror/state";
   import { EditorView, drawSelection } from "@codemirror/view";
+  import { history } from "@codemirror/commands";
   import { markdown } from "@codemirror/lang-markdown";
   import { Vim, getCM, vim } from "@replit/codemirror-vim";
   import { markdownLivePreview } from "./markdownLivePreview";
@@ -95,6 +96,7 @@
       doc,
       extensions: [
         vim(),
+        history(),
         drawSelection(),
         markdown(),
         markdownLivePreview({ resolveImageSrc: untrack(() => resolveImageSrc) }),

src/lib/NotesEditor.test.ts

@@ -138,6 +138,46 @@ describe("NotesEditor", () => {
     expect(get(focusTarget)).toEqual({ type: "note", filename: "a.md", folder: "Project Alpha" });
   });
 
+  it("supports vim undo (u) to revert typed text", async () => {
+    vi.mocked(command).mockImplementation((commandName: string) => {
+      if (commandName === "read_note") {
+        return Promise.resolve("original");
+      }
+
+      if (commandName === "write_note") {
+        return Promise.resolve(undefined);
+      }
+
+      return Promise.resolve(undefined);
+    });
+
+    focusTarget.set({ type: "notes-editor", folder: "Project Alpha" });
+
+    render(NotesEditor);
+    const user = userEvent.setup();
+
+    const editor = await screen.findByTestId("note-code-editor");
+    const textbox = within(editor).getByRole("textbox");
+    textbox.focus();
+
+    // Enter insert mode, type text, return to normal mode
+    await user.keyboard("A");  // append at end of line
+    await user.keyboard(" added");
+    await user.keyboard("{Escape}");
+
+    await waitFor(() => {
+      expect(editor).toHaveTextContent("original added");
+    });
+
+    // Press 'u' to undo
+    await user.keyboard("u");
+
+    await waitFor(() => {
+      expect(editor).toHaveTextContent("original");
+      expect(editor).not.toHaveTextContent("original added");
+    });
+  });
+
   it("keeps the latest note content when read_note resolves out of order", async () => {
     const noteARequest = deferred<string>();
     const noteBRequest = deferred<string>();