Fix layer text editing and expand fonts

[mgalpert]

What changed

• makes the layer name field update the rendered canvas text immediately
• preserves focus while editing inspector controls
• adds five self-hosted OFL fonts for seven total font choices
• adds GitHub, YouTube, X, Spotify, and Apple Podcasts links to the bottom of the left sidebar
• adds a single-column mobile workspace with touch-sized controls and versioned assets
• models the uploaded background as a selectable image layer
• lets users drag, zoom, center, and reset the image crop
• adds square, landscape, portrait, and vertical canvas aspect ratios
• preserves text sizes when switching formats and exports at the selected dimensions
• adds a 1200×630 social card assembled from two equal square layouts
• includes the reproducible Cover Grid preset and exported Already Here Tools square

Why

The editor now treats both text and artwork as controllable layout layers. Uploaded images preserve their natural proportions while users choose the crop for each output format, and shared links now present a grid-aligned branded tool preview.

Validation

• node --check app.js
• git diff --check
• browser-tested a 1672×941 upload, drag, 150% zoom, and crop reset
• browser-tested 1:1, 16:9, 4:5, and 9:16 format switching
• verified repeated ratio changes do not shrink typography
• exported and inspected a 3000×3000 tools square directly from Cover Grid
• verified primary text layers have a 0px left/right margin delta
• joined two 570×570 squares with equal outer margins and a fixed gutter
• verified the live 1200×630 image and versioned Open Graph metadata
• deployed to https://alreadyhere.show/tools/layout/