Switch icons from a webfont to self-hosted SVG masks — the webfont was the actual problem

Self-hosting Font Awesome's font files (previous commit) didn't fix it either: every icon in the picker still failed identically. That rules out CDN/network blocking specifically and points to something in the browser blocking custom webfont loading altogether regardless of origin (common with strict anti-fingerprinting protection, e.g. Brave's font blocking or certain privacy extensions — @font-face loading is a well-known fingerprinting vector).

Replaced the whole mechanism: each of the 258 curated icons is now a real downloaded SVG file (static/icons/*.svg, sourced from Font Awesome 5 Free's official SVG package) displayed via CSS mask-image (.icon-svg in style.css) instead of a font glyph. A masked SVG isn't a font resource at all, so it isn't subject to webfont-blocking — and it still colors via the existing "color" style property (background-color:currentColor) and sizes via font-size (1em), so no change to how the widget's other controls work.

The "Icône" widget now stores just the icon's slug (e.g. "trophy") in a dedicated attribute instead of a full CSS class string, rendered by a new special_render (render_icone.py). Updated the add-gallery and the properties-panel picker modal to use the same mask technique for their previews, and element_add.py to validate the slug against the curated list. Removed the now-unused self-hosted Font Awesome CSS/webfont files and the <link> tags — no font dependency left for icons at all.

Verified end to end (gallery renders with real SVG previews, simulated add creates a correctly-attributed element, the SVG file is actually served, the per-element picker reflects the current icon). Full suite green (89).

static/icons/building.svg

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+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!-- Font Awesome Free 5.15.4 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) --><path d="M436 480h-20V24c0-13.255-10.745-24-24-24H56C42.745 0 32 10.745 32 24v456H12c-6.627 0-12 5.373-12 12v20h448v-20c0-6.627-5.373-12-12-12zM128 76c0-6.627 5.373-12 12-12h40c6.627 0 12 5.373 12 12v40c0 6.627-5.373 12-12 12h-40c-6.627 0-12-5.373-12-12V76zm0 96c0-6.627 5.373-12 12-12h40c6.627 0 12 5.373 12 12v40c0 6.627-5.373 12-12 12h-40c-6.627 0-12-5.373-12-12v-40zm52 148h-40c-6.627 0-12-5.373-12-12v-40c0-6.627 5.373-12 12-12h40c6.627 0 12 5.373 12 12v40c0 6.627-5.373 12-12 12zm76 160h-64v-84c0-6.627 5.373-12 12-12h40c6.627 0 12 5.373 12 12v84zm64-172c0 6.627-5.373 12-12 12h-40c-6.627 0-12-5.373-12-12v-40c0-6.627 5.373-12 12-12h40c6.627 0 12 5.373 12 12v40zm0-96c0 6.627-5.373 12-12 12h-40c-6.627 0-12-5.373-12-12v-40c0-6.627 5.373-12 12-12h40c6.627 0 12 5.373 12 12v40zm0-96c0 6.627-5.373 12-12 12h-40c-6.627 0-12-5.373-12-12V76c0-6.627 5.373-12 12-12h40c6.627 0 12 5.373 12 12v40z"/></svg>