… warning

node:24-alpine has no Fontconfig installation. When Sharp composites an SVG
overlay that contains <text> elements, libvips internally calls into
librsvg/Pango to render it. Pango uses Fontconfig to locate system fonts;
without a Fontconfig config file the process prints:

  Fontconfig error: Cannot load default config file: No such file: (null)

This is non-fatal (the SVG is still rendered with a fallback glyph set) but
it floods the container log on every watermark/text request.

Fix: install fontconfig and ttf-dejavu (a standard, complete free font family
covering Latin, Greek, Cyrillic, etc.) in the runtime stage, then rebuild
the font cache with fc-cache -f so Fontconfig finds the config file.

ttf-dejavu is chosen because:
  - Available in Alpine apk with no extra repos
  - Covers the most common scripts users will embed in watermarks
  - Small (~1 MB compressed)