* Add dynamic OG image and use large Twitter cards
Generate a 1200x630 OG image with the cmux logo, tagline, and
description using next/og ImageResponse. Switch Twitter card type
from "summary" to "summary_large_image" across all pages so shared
links show a full-width preview instead of the tiny favicon thumbnail.
* Use Geist font and app screenshot in OG image, update landing/README images
Replace the centered text-only OG image with a split layout: branding
on the left (logo, name, tagline) and a full app screenshot on the
right. Load Geist Regular/SemiBold from Google Fonts for consistent
typography. Replace the homepage landing image and README screenshot
with a new screenshot showing cmux with multiple workspaces, tabs,
browser panel, and code diffs.
* Fine-tune OG image layout and update homepage/README screenshots
Apply tuned values from OG editor: 112px logo, 48px title with -8
translateY, 34px subtitle at #cfcfcf, 320px fade height. Use Geist
font loaded from Google Fonts. Render at 2x (2400x1260) for sharper
previews on social platforms. Remove GitHub URL from footer.
Add pre-resized og-screenshot.png (2208px wide) for the OG image to
avoid Satori downscale blur. Update homepage landing image and README
screenshot with new app screenshot.
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Co-authored-by: Lawrence Chen <lawrencecchen@users.noreply.github.com>