test: address review feedback on e2e tests

- colors: use cross-platform MOD modifier instead of hardcoded Control in
  the background-color-mark test, and document the post-insertHeading wait
- emojipicker: wait before asserting the picker is absent so the negative
  check isn't won by a race
- Dockerfile: align Corepack's prepared pnpm with the repo's packageManager
  pin (11.5.1)

Author: nperez0111

tests/Dockerfile

@@ -24,7 +24,7 @@ FROM mcr.microsoft.com/playwright:v1.51.1-noble
 WORKDIR /work
 
 # pnpm matching the repo's packageManager.
-RUN corepack enable && corepack prepare pnpm@11.1.1 --activate
+RUN corepack enable && corepack prepare pnpm@11.5.1 --activate
 
 # Copy ONLY the dependency manifests — every workspace member's package.json plus
 # the lockfile/workspace file — preserving their paths with --parents. These are

tests/src/end-to-end/colors/colors.test.tsx

@@ -70,6 +70,8 @@ describe("Check Background & Text Color Functionality", () => {
     await userEvent.keyboard("{Enter}");
     await insertHeading(3);
 
+    // Wait for the headings to finish rendering before navigating the caret,
+    // otherwise the subsequent ArrowUp/selection can land in a stale layout.
     await sleep(500);
 
     await userEvent.keyboard("{ArrowUp}");
@@ -97,9 +99,7 @@ describe("Check Background & Text Color Functionality", () => {
 
     await userEvent.keyboard("{ArrowUp}");
     await userEvent.keyboard(`{${MOD}>}{ArrowLeft}{/${MOD}}`);
-    await userEvent.keyboard(
-      "{Control>}{Shift>}{ArrowRight}{/Shift}{/Control}",
-    );
+    await userEvent.keyboard(`{${MOD}>}{Shift>}{ArrowRight}{/Shift}{/${MOD}}`);
 
     await userEvent.click(await waitForSelector(COLORS_BUTTON_SELECTOR));
     await userEvent.click(

tests/src/end-to-end/emojipicker/emojipicker.test.tsx

@@ -24,6 +24,9 @@ describe("Check Emoji Picker Functionality", () => {
   test("should not show emoji picker when : is typed", async () => {
     await focusOnEditor();
     await openEmojiPicker();
+    // Give the editor a chance to (incorrectly) open the picker before
+    // asserting its absence, so the negative check isn't won by a race.
+    await sleep(500);
     expect(document.querySelectorAll(EMOJI_PICKER_SELECTOR).length).toBe(0);
   });
   test("should show emoji picker when : and query is typed", async () => {