feat: add sequential Following review pass (Closes #1299)

tests/e2e/test_mobile_following_release.py

@@ -25,11 +25,14 @@ def test_following_queue_is_phone_usable_at_narrow_viewport():
         page.locator("#following-list").evaluate("""node => {
           node.innerHTML = '<button class="following-card has-unseen-change" type="button"><span><em>New activity</em><strong>Changed issue with a long mobile title</strong><small>stackchain/api #42 · open · just now</small></span><span aria-hidden="true">›</span></button>';
         }""")
+        page.locator("#review-following").evaluate("node => node.hidden = false")
         page.locator("#following-sheet").evaluate("node => node.showModal()")
 
         expect(page.locator("#following-sheet")).to_be_visible()
         expect(page.locator(".following-card")).to_be_visible()
         expect(page.locator(".following-card")).to_contain_text("New activity")
+        expect(page.locator("#review-following")).to_have_text("Review new activity")
+        assert page.locator("#review-following").bounding_box()["height"] >= 44
         assert page.locator(".following-card").bounding_box()["height"] >= 44
         assert page.locator("#close-following").bounding_box()["height"] >= 44
         overflow = page.evaluate("document.documentElement.scrollWidth > document.documentElement.clientWidth")