Rewrite moongreet from Python to Rust (v0.3.0)

Complete rewrite of the greetd greeter from Python/PyGObject to Rust/gtk4-rs
for consistency with moonset, single binary without Python runtime, and
improved security through Rust memory safety.

Modules: main, greeter, ipc, config, i18n, users, sessions, power
86 unit tests covering all modules including login_worker IPC flow.
Security hardening: shell-word splitting for exec_cmd, absolute path
validation for session binaries, session-name sanitization, absolute
loginctl path, atomic IPC writes.

pkg/PKGBUILD

@@ -4,24 +4,20 @@
 # Maintainer: Dominik Kressler
 
 pkgname=moongreet-git
-pkgver=0.2.0.r0.g64f08d7
+pkgver=0.3.0.r0.g0000000
 pkgrel=1
-pkgdesc="A greetd greeter for Wayland, built with Python + GTK4 + gtk4-layer-shell"
-arch=('any')
+pkgdesc="A greetd greeter for Wayland with GTK4 and Layer Shell"
+arch=('x86_64')
 url="https://gitea.moonarch.de/nevaforget/greetd-moongreet"
 license=('MIT')
 depends=(
-    'python'
-    'python-gobject'
     'gtk4'
     'gtk4-layer-shell'
     'greetd'
 )
 makedepends=(
     'git'
-    'python-build'
-    'python-installer'
-    'python-hatchling'
+    'cargo'
 )
 provides=('moongreet')
 conflicts=('moongreet')
@@ -36,13 +32,12 @@ pkgver() {
 
 build() {
     cd "$srcdir/greetd-moongreet"
-    rm -rf dist/
-    python -m build --wheel --no-isolation
+    cargo build --release --locked
 }
 
 package() {
     cd "$srcdir/greetd-moongreet"
-    python -m installer --destdir="$pkgdir" dist/*.whl
+    install -Dm755 target/release/moongreet "$pkgdir/usr/bin/moongreet"
 
     # Greeter config
     install -Dm644 config/moongreet.toml "$pkgdir/etc/moongreet/moongreet.toml"