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/crown.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 640 512"><!-- 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="M528 448H112c-8.8 0-16 7.2-16 16v32c0 8.8 7.2 16 16 16h416c8.8 0 16-7.2 16-16v-32c0-8.8-7.2-16-16-16zm64-320c-26.5 0-48 21.5-48 48 0 7.1 1.6 13.7 4.4 19.8L476 239.2c-15.4 9.2-35.3 4-44.2-11.6L350.3 85C361 76.2 368 63 368 48c0-26.5-21.5-48-48-48s-48 21.5-48 48c0 15 7 28.2 17.7 37l-81.5 142.6c-8.9 15.6-28.9 20.8-44.2 11.6l-72.3-43.4c2.7-6 4.4-12.7 4.4-19.8 0-26.5-21.5-48-48-48S0 149.5 0 176s21.5 48 48 48c2.6 0 5.2-.4 7.7-.8L128 416h384l72.3-192.8c2.5.4 5.1.8 7.7.8 26.5 0 48-21.5 48-48s-21.5-48-48-48z"/></svg>