test(collections): change sources only after the page's selected-file read is answered

The details panel reads its selected file as soon as the page lists. When the
test's source change landed before that read was answered, the page found the
file again on its own (409 -> rescope -> relist), so the card under the old
numbering the test was about to click was gone. Every test in the spec now
waits for that read before changing sources.

Closes #484

tests/browser/workspace-stale-source.spec.mjs

@@ -37,6 +37,15 @@ test.afterEach(async ({ page, request, browserName }) => {
     await expect(await request.post('/__test__/tagging/reset', { data: {} })).toBeOK();
 });
 
+async function openSettled(page, url) {
+    // The page reads its selected file's details as soon as it lists. A source change before that read is answered
+    // makes the page find the file again on its own, so the test's old-numbering locators are gone before they are
+    // used (#484): every test changes sources only after the read was answered.
+    const inspected = page.waitForResponse(item => new URL(item.url()).pathname.startsWith('/prompt_manager/images/inspect/') &&
+        item.request().method() === 'GET');
+    await page.goto(url);
+    expect((await inspected).status()).toBe(200);
+}
 async function openTag(page, path = FIRST, root = 0) {
     const observed = answered(page, '/image-annotations/observe');
     await tagButton(page, path, root).click();
@@ -53,7 +62,7 @@ async function savedTags(request, path, root) {
 }
 
 test('renumbered sources under an open Tag dialog: it finds the file again, keeps the draft and Generate works', async ({ page, request }) => {
-    await page.goto(images);
+    await openSettled(page, images);
     await expect(card(page, FIRST)).toHaveClass(/\bselected\b/);
     expect((await openTag(page)).status()).toBe(200);
     await manual(page).fill('kept_draft');
@@ -91,7 +100,7 @@ test('renumbered sources under an open Tag dialog: it finds the file again, keep
 });
 
 test('the inspector finds a renumbered file again; checked files from the old numbering are cleared', async ({ page, request }) => {
-    await page.goto(images);
+    await openSettled(page, images);
     await expect(card(page, FIRST)).toHaveClass(/\bselected\b/);
     await card(page, FIRST).getByRole('checkbox', { name: /^Select / }).check();
     await expect(page.locator('.bulkbar')).toBeVisible();
@@ -113,7 +122,7 @@ test('the inspector finds a renumbered file again; checked files from the old nu
 });
 
 test('a scope that cannot be mapped: Generate and Save are visibly disabled, the reason and Refresh sit beside them', async ({ page }) => {
-    await page.goto(images);
+    await openSettled(page, images);
     await expect(card(page, FIRST)).toBeVisible();
     await expect(await page.request.post('/__test__/scope-key/rotate')).toBeOK();
     const rescoped = answered(page, '/images/rescope');
@@ -157,7 +166,7 @@ test('a scope that cannot be mapped: Generate and Save are visibly disabled, the
 });
 
 test('an unmappable inspector read keeps its visible Refresh, and Refresh recovers the panel', async ({ page }) => {
-    await page.goto(images);
+    await openSettled(page, images);
     await expect(card(page, FIRST)).toHaveClass(/\bselected\b/);
     await expect(await page.request.post('/__test__/scope-key/rotate')).toBeOK();
     const rescoped = answered(page, '/images/rescope');
@@ -173,7 +182,7 @@ test('an unmappable inspector read keeps its visible Refresh, and Refresh recove
 
 test('a Load more cursor the server cannot verify offers Refresh instead of a dead Retry', async ({ page, request }) => {
     await expect(await request.post('/__test__/tagging/reset', { data: { extra_images: 60 } })).toBeOK();
-    await page.goto(images);
+    await openSettled(page, images);
     await expect(cards(page).first()).toBeVisible();
     await expect(page.locator('#gallery-continuation')).toContainText('more load as you scroll');
     await expect(await request.post('/__test__/scope-key/rotate')).toBeOK();
@@ -191,7 +200,7 @@ test('a Load more cursor the server cannot verify offers Refresh instead of a de
 });
 
 test('a viewer whose media source was renumbered closes onto the file, kept selected', async ({ page, request }) => {
-    await page.goto(images);
+    await openSettled(page, images);
     await expect(card(page, FIRST)).toHaveClass(/\bselected\b/);
     await expect(await request.post('/__test__/sources/reverse')).toBeOK();
     const rescoped = answered(page, '/images/rescope');
@@ -217,7 +226,7 @@ test('a collection page finds a renumbered member again and stays on its members
     await expect(added).toBeOK();
     const collections = (await (await request.get('/prompt_manager/collections')).json()).collections;
     const { id } = collections.find(item => item.name === name);
-    await page.goto(`/prompt_manager/workspace#/collection/${id}`);
+    await openSettled(page, `/prompt_manager/workspace#/collection/${id}`);
     await expect(cards(page)).toHaveCount(1);
     await expect(card(page, FIRST)).toHaveClass(/\bselected\b/);
     await expect(await request.post('/__test__/sources/reverse')).toBeOK();