fonts: fall back to fontconfig when a pinned font path is missing (0.4.2)

A config generated on one machine pinned
/usr/share/fonts/google-noto/NotoSans-Regular.ttf; on another host the
same package installs under fonts/noto, so the shared config made the
fontloader thread panic ("Font file not found") and, with panic =
"abort", kill wldash before a window appeared.

resolve_font_path() now uses a pinned path only if the file exists,
otherwise asks fontconfig for the name (what fc-match does) and says so
on stderr. find_font() and FontLoader::from_path() return errors
instead of unwrapping, and an unresolvable font exits with one clear
line. Generated configs leave font_paths unset so names resolve per
machine; pinning remains possible by hand.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

PKGBUILD

@@ -4,7 +4,7 @@
 # project.uhhm.no (namespace bl). pkgver is the version; the tag has
 # to agree with it and with Cargo.toml.
 pkgname=wldash
-pkgver=0.4.1
+pkgver=0.4.2
 pkgrel=1
 pkgdesc="Dashboard/launcher/control-panel for wlroots-style Wayland compositors (layer-shell)"
 arch=('x86_64' 'aarch64')