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.

README.md

@@ -1,51 +1,58 @@
 # Moongreet
 
-A greetd greeter for Wayland, built with Python + GTK4 + gtk4-layer-shell.
+A greetd greeter for Wayland, built with Rust + GTK4 + gtk4-layer-shell.
 Part of the Moonarch ecosystem.
 
 ## Features
 
 - **greetd IPC** — Communicates via `$GREETD_SOCK` (length-prefixed JSON)
 - **User list** — Parsed from `/etc/passwd` (UID 1000–65533)
-- **Avatars** — AccountsService icons, `~/.face` fallback, default SVG
+- **Avatars** — AccountsService icons, `~/.face` fallback, default SVG with theme tinting
 - **Sessions** — Discovered from `/usr/share/wayland-sessions/` and `/usr/share/xsessions/`
-- **Last user** — Remembered in `/var/cache/moongreet/last-user`
+- **Last user/session** — Remembered in `/var/cache/moongreet/`
 - **Power actions** — Reboot / Shutdown via `loginctl`
-- **Layer Shell** — Fullscreen via gtk4-layer-shell
+- **Layer Shell** — Fullscreen via gtk4-layer-shell (TOP layer)
+- **Multi-monitor** — Greeter on primary, wallpaper on all monitors
+- **i18n** — German and English (auto-detected from system locale)
+- **Faillock warning** — Warns after 2 failed attempts, locked message after 3
 
 ## Requirements
 
-- Python 3.11+
-- GTK 4, PyGObject
+- GTK 4
 - gtk4-layer-shell (for Wayland fullscreen)
 - greetd
 
+## Building
+
+```bash
+cargo build --release
+```
+
 ## Installation
 
 ```bash
-uv pip install .
+# Install binary
+sudo install -Dm755 target/release/moongreet /usr/bin/moongreet
+
+# Install config
+sudo mkdir -p /etc/moongreet
+sudo cp config/moongreet.toml /etc/moongreet/moongreet.toml
 ```
 
 ## System Setup
 
-1. Copy configuration:
-   ```bash
-   sudo mkdir -p /etc/moongreet
-   sudo cp config/moongreet.toml /etc/moongreet/moongreet.toml
-   ```
+1. Edit `/etc/moongreet/moongreet.toml` — set an absolute path for the wallpaper.
 
-2. Edit `/etc/moongreet/moongreet.toml` — set an absolute path for the wallpaper.
-
-3. Create cache directory:
+2. Create cache directory:
    ```bash
-   sudo mkdir -p /var/cache/moongreet
+   sudo mkdir -p /var/cache/moongreet/last-session
    sudo chown greeter:greeter /var/cache/moongreet
    ```
 
-4. Configure greetd (`/etc/greetd/config.toml`):
+3. Configure greetd (`/etc/greetd/config.toml`):
    ```ini
    [default_session]
-   command = "moongreet"
+   command = "niri -c /etc/greetd/niri-greeter.kdl"
    user = "greeter"
    ```
 
@@ -53,13 +60,13 @@ uv pip install .
 
 ```bash
 # Run tests
-uv run pytest tests/ -v
+cargo test
 
-# Type checking
-uv run pyright src/
+# Build release
+cargo build --release
 
-# Run locally (without greetd)
-uv run moongreet
+# Run locally (without greetd, needs LD_PRELOAD for layer-shell)
+LD_PRELOAD=/usr/lib/libgtk4-layer-shell.so ./target/release/moongreet
 ```
 
 ## License