Add crash guard, logging, and defensive error handling to prevent lockout

Global sys.excepthook unlocks the session on unhandled exceptions.
Structured logging to stderr and optional file at /var/cache/moonlock/.
Window creation, CSS loading, and fingerprint start wrapped in
try/except with automatic session unlock when all windows fail.

pkg/PKGBUILD

@@ -4,7 +4,7 @@
 # Maintainer: Dominik Kressler
 
 pkgname=moonlock-git
-pkgver=0.1.1.r0.g22f725e
+pkgver=0.2.0.r0.g7cee4f4
 pkgrel=1
 pkgdesc="A secure Wayland lockscreen with GTK4, PAM and fingerprint support"
 arch=('any')