fix(editor): resync WebKit caret after paste

apps/desktop/src/lib/__tests__/editor/queryEditorPasteCaretResync.spec.ts

@@ -0,0 +1,36 @@
+import { readFileSync } from "node:fs";
+import { EditorSelection } from "@codemirror/state";
+import { describe, expect, it } from "vitest";
+import { computePasteCaretResyncTarget } from "@/lib/editor/queryEditorPasteCaretResync";
+
+const queryEditorSource = readFileSync(new URL("../../../components/editor/QueryEditor.vue", import.meta.url), "utf8");
+
+describe("computePasteCaretResyncTarget", () => {
+  it("nudges a single caret forward when there is room", () => {
+    expect(computePasteCaretResyncTarget(EditorSelection.single(3), 10)).toBe(4);
+  });
+
+  it("nudges a single caret backward at the end of the document", () => {
+    expect(computePasteCaretResyncTarget(EditorSelection.single(10), 10)).toBe(9);
+  });
+
+  it("does not collapse multiple CodeMirror cursors", () => {
+    const selection = EditorSelection.create([EditorSelection.cursor(2), EditorSelection.cursor(6)]);
+    expect(computePasteCaretResyncTarget(selection, 10)).toBeNull();
+  });
+
+  it("does not replace a non-empty selection with a caret", () => {
+    expect(computePasteCaretResyncTarget(EditorSelection.single(2, 5), 10)).toBeNull();
+  });
+
+  it("returns null for an empty document", () => {
+    expect(computePasteCaretResyncTarget(EditorSelection.single(0), 0)).toBeNull();
+  });
+});
+
+describe("QueryEditor paste caret resync wiring", () => {
+  it("resyncs only an unchanged single caret after an input.paste transaction", () => {
+    expect(queryEditorSource).toMatch(/update\.transactions\.some\(\(tr\) => tr\.isUserEvent\("input\.paste"\)\)[\s\S]*?resyncCaretAfterPaste\(update\.view\)/);
+    expect(queryEditorSource).toMatch(/computePasteCaretResyncTarget\(selection, view\.state\.doc\.length\)/);
+  });
+});

apps/desktop/src/lib/editor/queryEditorPasteCaretResync.ts

@@ -0,0 +1,24 @@
+/**
+ * WebKit (Safari / macOS WKWebView) bug: after CodeMirror replaces DOM text
+ * nodes for a paste, `document.getSelection()` reports the correct caret
+ * position, but WebKit's native typing insertion point silently keeps
+ * pointing at the pre-paste position — the next typed character lands there
+ * instead of after the pasted text (e.g. typing "," after pasting "2" into
+ * "1,|)" produces "1,,2)" instead of "1,2,)"). A genuine subsequent selection
+ * change (as from an arrow key) forces WebKit to re-anchor correctly.
+ *
+ * Returns a nearby position to briefly move the caret to (and back from)
+ * to replicate that nudge, or null if there is nowhere to nudge to.
+ */
+export interface PasteCaretSelection {
+  ranges: readonly unknown[];
+  main: { empty: boolean; head: number };
+}
+
+export function computePasteCaretResyncTarget(selection: PasteCaretSelection, docLength: number): number | null {
+  if (selection.ranges.length !== 1 || !selection.main.empty) return null;
+  const head = selection.main.head;
+  const nudged = head < docLength ? head + 1 : head - 1;
+  if (nudged === head || nudged < 0) return null;
+  return nudged;
+}