Scroll capture test pages

Long pages for exercising a scrolling screenshot: predictable text, no images, no network requests, and deliberately awkward chrome.

• 01 · light vertical Plain long page on a light background.
• 02 · dark vertical The same page dark, where seams show differently.
• 03 · sticky header and fixed footer Chrome that stays put while the content moves, which is what trips naive stitching.
• 04 · horizontal Scrolls sideways instead of down.