test(post-form): realign photo specs to FilePond after U4 rework

waitForPhotoUpload waits on FilePond processing-complete; AE1/AE4 use
input.filepond--browser + the .photo-convert-status error status; V3/V4 back
to FilePond limit + non-image rejection; reauth hint -> .photo-reauth-hint;
test-form-config asserts type:filepond. Verified against a live server via a
browser smoke run (HEIC->JPEG attach, corrupt fail-closed, draft restore).

tests/ui/post/post.spec.js

@@ -54,7 +54,7 @@ test.skip('P2: post entry with photo → photo saved in entry folder and visible
     await page.fill('input[name="data[location_city]"]', 'Testville');
     await page.fill('input[name="data[location_country]"]', 'Testland');
 
-    await page.locator('input.photo-picker__input').setInputFiles(TEST_PHOTO);
+    await page.locator('input.filepond--browser').setInputFiles(TEST_PHOTO);
     await waitForPhotoUpload(page);
 
     await page.locator('.btn-post').evaluate(el => el.click());