Android PWA viewport-fit mode switch sampler

Isolate browser behavior from the original page

This sampler removes the native select dialog, responsive card layout, theme colors, and orientation lock. It keeps only fixed top and bottom bars, safe-area padding, mode switching, and geometry telemetry.

• Open repro.html in the Chromium build under test.
• Use the Chrome menu and choose Install and create shortcut, then Install.
• Launch Fit Switch from the home screen.
• Switch modes using the three page buttons and rotate the device.
• Compare the cyan left marker, amber right marker, system-bar surfaces, and telemetry.

• If the artifact remains, it is independent of the original sampler's select dialog and centered card CSS.
• If it disappears, compare the original page's native select, fixed elements, and max-width layout separately.
• The manifest intentionally omits theme and background colors to match the original test site.