Rewrite srdwm in Rust: working X11 and Wayland backends, Lua config

The C++ prototype (moved to legacy-cpp/) was mostly a design skeleton:
X11 and Windows backends were partially real, Wayland created the
wlroots object graph but never wired a single event listener, macOS
was stub except monitor enumeration, and the Lua engine's srd.bind()
stored a key-combo string but never the actual closure. See
docs/PRIOR_ART.md for the full audit.

This replaces it with a Cargo workspace:

- srdwm-core: platform-independent window/workspace/monitor state,
  a real master-stack tiling layout, and SmartPlacement grid/cascade/
  snap-to-edge placement - fixing several bugs in the C++ version
  (hardcoded 2-column grid, cascade that never cascaded, snap-to-edge
  that always returned a fixed rect). 35 unit tests.
- srdwm-config: the srd Lua API via mlua, implementing the surface
  docs/DEFAULTS.md always documented but the C++ engine never actually
  built (srd.window.close()/focus(direction), srd.workspace.next(),
  real keybinding closures, require("srd") support). 10 unit tests.
- srdwm-x11: a real reparenting WM with a drawn title bar (buttons,
  drag, resize), verified live under Xephyr - frame placement and
  client offset match srdwm-core's computed geometry exactly, and the
  decoration renders correctly on screen.
- srdwm-wayland: a from-scratch smithay compositor (the C++ version
  had nothing working to port from) - runs via the winit backend,
  tracks xdg-shell toplevels through the same WindowManager and
  hit-testing code X11 uses, verified to start/render/run without
  crashing. Decorations are solid-color (no text yet); see
  docs/IMPLEMENTATION_STATUS.md for exact scope.
- srdwm-windows / srdwm-macos: structured, cfg-gated designs informed
  by komorebi/glazewm and yabai/AeroSpace respectively (see
  docs/PRIOR_ART.md), honestly marked as unbuilt/unverified since this
  sandbox has no Windows or macOS target.

1 files changed, 50 insertions, 427 deletions

diff --git a/README.md b/README.md
index c59982d..618d5ff 100644
--- a/README.md
+++ b/README.md
@@ -1,462 +1,85 @@
-# SRDWM - Cross-Platform Window Manager
+# SRDWM
 
-SRDWM is a modern, cross-platform window manager that provides a unified window management experience across Linux (X11/Wayland), Windows, and macOS. It features smart window placement, togglable decorations, and easy switching between tiling and floating layouts.
+A cross-platform window manager, configured entirely in Lua, aiming to feel
+like a native window manager on every platform it targets rather than a
+compromise between them: real title bars with drag/resize/minimize/maximize/close
+on every backend that can support them, not just a border.
 
-## Features
+This is a Rust rewrite of an earlier C++ prototype (preserved at
+[`legacy-cpp/`](legacy-cpp/)); see [`docs/PRIOR_ART.md`](docs/PRIOR_ART.md)
+for what carried over, what got fixed, and what other window managers
+informed the design.
 
-### **Cross-Platform Support**
-- **Linux X11**: Full server-side decoration control with frame windows
-- **Linux Wayland**: Modern wlroots compositor with zxdg-decoration protocol
-- **Windows**: Native DWM border integration with global hooks
-- **macOS**: Platform-constrained but functional with overlay windows
+## Status
 
-### **Smart Window Placement**
-- **Windows 11-style grid placement** with optimal cell sizing
-- **Cascade placement** for overlapping windows
-- **Snap-to-edge** functionality
-- **Overlap detection** and free space finding algorithms
+Linux is the primary target and the only one verified end-to-end so far:
 
-### **Window Management**
-- **Togglable decorations** with custom border colors and widths
-- **Easy tiling/floating toggle** with per-window state management
-- **Multiple layout engines**: Tiling, Dynamic, and Floating modes
-- **Smart placement integration** for floating windows
+| Backend | Status |
+|---|---|
+| X11 | Working - reparenting WM with a drawn title bar (buttons, drag, resize), verified live under Xephyr |
+| Wayland | Working, smaller scope - real `smithay` compositor, verified to run; decorations have no text yet, global keybindings use a coarse heuristic |
+| Windows | Designed, not built (no Windows target in dev sandbox) |
+| macOS | Designed, not built (no macOS target in dev sandbox) |
 
-### **Lua Configuration**
-- **Scriptable configuration** with full Lua API
-- **Real-time configuration reloading**
-- **Platform-specific keybindings** and settings
-- **Theme and decoration customization**
+Full detail, including exactly what's real vs. stubbed and why, is in
+[`docs/IMPLEMENTATION_STATUS.md`](docs/IMPLEMENTATION_STATUS.md). Crate
+layout and design rationale are in [`docs/ARCHITECTURE.md`](docs/ARCHITECTURE.md).
 
-## Requirements
+## Building
 
-### **Linux (X11)**
 ```bash
-# Ubuntu/Debian
-sudo apt install build-essential cmake pkg-config liblua5.4-dev \
-    libx11-dev libxrandr-dev libxinerama-dev libxcb-dev \
-    libxcb-keysyms1-dev libxcb-icccm4-dev
-
-# Fedora
-sudo dnf install gcc-c++ cmake pkgconfig lua-devel \
-    libX11-devel libXrandr-devel libXinerama-devel libxcb-devel \
-    libxcb-keysyms-devel libxcb-icccm-devel
-
-# Arch Linux
-sudo pacman -S base-devel cmake pkgconf lua \
-    libx11 libxrandr libxinerama libxcb \
-    xcb-util xcb-util-keysyms xcb-util-wm
-```
-
-### **Linux (Wayland)**
-```bash
-# Ubuntu/Debian
-sudo apt install build-essential cmake pkg-config liblua5.4-dev \
-    libwayland-dev wayland-protocols libwlroots-dev
-
-# Fedora
-sudo dnf install gcc-c++ cmake pkgconfig lua-devel \
-    wayland-devel wayland-protocols-devel wlroots-devel
-
-# Arch Linux
-sudo pacman -S base-devel cmake pkgconf lua \
-    wayland wayland-protocols wlroots
-```
-
-### **Windows**
-- Visual Studio 2019 or later with C++17 support
-- CMake 3.16 or later
-- Lua 5.4 or later
-
-### **macOS**
-```bash
-# Install dependencies via Homebrew
-brew install cmake lua pkg-config
-
-# Install Xcode Command Line Tools
-xcode-select --install
-```
-
-## Installation
-
-### **Quick Start (Linux/macOS)**
-```bash
-# Clone and bootstrap (deps + build + test + install)
-git clone https://github.com/srdusr/srdwm.git
-cd srdwm
-bash scripts/bootstrap.sh --all
-
-# X11-only build
-# bash scripts/bootstrap.sh --all --no-wayland
-# Real Wayland backend (requires wlroots deps)
-# bash scripts/bootstrap.sh --all --real-wayland
+cargo build --workspace
+cargo test --workspace
 ```
 
-### **Building from Source**
+Linux needs the usual X11/Wayland/EGL/GLES/xkbcommon/libinput/libseat
+development headers (`x11rb` and `smithay` link against them); on Arch:
 
-1. **Clone the repository**
 ```bash
-git clone https://github.com/srdusr/srdwm.git
-cd srdwm
+sudo pacman -S libx11 libxcb wayland wayland-protocols egl-wayland \
+    mesa xkbcommon libinput libseat lua54
 ```
 
-2. **Create build directory**
-```bash
-mkdir build
-cd build
-```
+`mlua` builds Lua 5.4 from source (`vendored` feature), so no system Lua
+package is required.
 
-3. **Configure and build**
-```bash
-cmake -S . -B build
-cmake --build build -j$(nproc)
-```
+## Running
 
-4. **Install**
 ```bash
-sudo cmake --install build --prefix /usr/local
+cargo run -p srdwm
 ```
 
-### **Platform-Specific Installation**
+Backend selection is automatic: Wayland if `WAYLAND_DISPLAY` or
+`XDG_SESSION_TYPE=wayland` is set, X11 otherwise (override by unsetting
+those env vars). To try it without touching your real session, run it
+against a nested server:
 
-#### **Linux**
 ```bash
-# Install to system
-sudo cmake --install build --prefix /usr/local
-
-# Or install to user directory
-make install DESTDIR=$HOME/.local
-```
-
-#### **Windows**
-```cmd
-# Build with Visual Studio
-cmake -G "Visual Studio 16 2019" -A x64 ..
-cmake --build . --config Release
-
-# Install
-cmake --install . --prefix "C:\Program Files\SRDWM"
-```
-
-#### **macOS**
-```bash
-# Build and install
-make -j$(sysctl -n hw.ncpu)
-sudo make install
+Xephyr :99 -screen 1280x800 &
+DISPLAY=:99 SRDWM_CONFIG_PATH="$PWD/config/srd" cargo run -p srdwm
 ```
 
 ## Configuration
 
-### **Basic Configuration**
-
-Create your configuration file at `~/.config/srdwm/init.lua`:
+Config lives at `$SRDWM_CONFIG_PATH`, or `$XDG_CONFIG_HOME/srdwm/srd`, or
+`~/.config/srdwm/srd`. [`config/srd/`](config/srd/) in this repo is a
+complete working example (`init.lua` loads `keybindings.lua`, `layouts.lua`,
+`themes.lua`, `monitors.lua`, `rules.lua`, `startup.lua`). Full API and
+default values: [`docs/DEFAULTS.md`](docs/DEFAULTS.md).
 
 ```lua
-- Basic SRDWM configuration
-print("Loading SRDWM configuration...")
-
-- Global settings
-srd.set("general.decorations_enabled", true)
-srd.set("general.border_width", 3)
-srd.set("general.border_color", "#2e3440")
-
-- Layout settings
-srd.set("general.default_layout", "dynamic")
-srd.set("general.smart_placement", true)
-
-- Keybindings
-srd.bind("Mod4+Return", function()
-    - Open terminal
-    srd.spawn("alacritty")
-end)
-
-srd.bind("Mod4+q", function()
-    - Close focused window
-    srd.window.close()
-end)
-
-srd.bind("Mod4+f", function()
-    - Toggle floating
-    local window = srd.window.focused()
-    if window then
-        srd.window.toggle_floating(window.id)
-    end
-end)
-
-- Layout switching
-srd.bind("Mod4+1", function() srd.layout.set("tiling") end)
-srd.bind("Mod4+2", function() srd.layout.set("dynamic") end)
-srd.bind("Mod4+3", function() srd.layout.set("floating") end)
-
-print("Configuration loaded successfully!")
-```
-
-### **Platform-Specific Configuration**
-
-#### **Linux X11**
-```lua
-- X11-specific settings
-if srd.get_platform() == "x11" then
-    srd.set("general.border_width", 3)
-    srd.set("general.decorations_enabled", true)
-    
-    - X11-specific keybindings
-    srd.bind("Mod4+x", function()
-        local window = srd.window.focused()
-        if window then
-            srd.window.set_decorations(window.id, not srd.window.get_decorations(window.id))
-        end
-    end)
-end
-```
-
-#### **Linux Wayland**
-```lua
-- Wayland-specific settings
-if srd.get_platform() == "wayland" then
-    srd.set("general.border_width", 2)
-    srd.set("general.decorations_enabled", true)
-    
-    - Wayland-specific keybindings
-    srd.bind("Mod4+w", function()
-        local window = srd.window.focused()
-        if window then
-            srd.window.set_decorations(window.id, not srd.window.get_decorations(window.id))
-        end
-    end)
-end
-```
-
-#### **Windows**
-```lua
-- Windows-specific settings
-if srd.get_platform() == "windows" then
-    srd.set("general.border_width", 2)
-    srd.set("general.decorations_enabled", true)
-    
-    - Windows-specific keybindings
-    srd.bind("Mod4+d", function()
-        local window = srd.window.focused()
-        if window then
-            srd.window.set_border_color(window.id, 255, 0, 0) - Red border
-        end
-    end)
-end
-```
-
-#### **macOS**
-```lua
-- macOS-specific settings
-if srd.get_platform() == "macos" then
-    srd.set("general.border_width", 1)
-    srd.set("general.decorations_enabled", false) - Limited support
-    
-    - macOS-specific keybindings
-    srd.bind("Mod4+m", function()
-        print("macOS: Overlay window toggle requested")
-    end)
-end
-```
-
-## Usage
-
-### **Starting SRDWM**
-
-#### **Linux**
-```bash
-# X11
-srdwm --platform x11
-
-# Wayland
-srdwm --platform wayland
-```
-
-#### **Windows**
-```cmd
-# Start from command line
-srdwm.exe
-
-# Or add to startup
-```
+local srd = require("srd")
 
-#### **macOS**
-```bash
-# Start from command line
-srdwm
-
-# Or add to login items
-```
-
-### **Keybindings**
-
-| Key | Action |
-|-----|--------|
-| `Mod4+Return` | Open terminal |
-| `Mod4+q` | Close focused window |
-| `Mod4+f` | Toggle floating |
-| `Mod4+1/2/3` | Switch layouts (tiling/dynamic/floating) |
-| `Mod4+b/n/r` | Change border colors (green/blue/red) |
-| `Mod4+0` | Reset decorations |
-| `Mod4+s` | Smart placement info |
-
-### **Layouts**
-
-- **Tiling**: Traditional tiling layout
-- **Dynamic**: Smart placement with Windows 11-style algorithms
-- **Floating**: Free-form window placement
-
-## Testing
-
-### **Running Tests**
-
-```bash
-# Build tests
-cd build
-make
-
-# Run all tests
-ctest
-
-# Run specific tests
-./tests/test_smart_placement
-./tests/test_platform_factory
-./tests/test_lua_manager
-```
-
-### **Platform-Specific Tests**
+srd.bind("Mod4+Return", function() srd.spawn("alacritty") end)
+srd.bind("Mod4+q", function() srd.window.close() end)
+srd.bind("Mod4+h", function() srd.window.focus("left") end)
 
-```bash
-# Linux X11
-./tests/test_x11_platform
-
-# Linux Wayland
-./tests/test_wayland_platform
+srd.layout.set("tiling")
+srd.layout.configure("tiling", { master_ratio = 0.6, gaps = { inner = 8, outer = 16 } })
 
-# Windows
-./tests/test_windows_platform
-
-# macOS
-./tests/test_macos_platform
+srd.theme.set_colors({ background = "#2e3440", accent = "#88c0d0" })
 ```
 
-### **One-command dependency installers**
-```bash
-# Ubuntu/Debian
-bash scripts/install_deps_ubuntu.sh
-
-# Fedora
-bash scripts/install_deps_fedora.sh
-
-# Arch Linux
-bash scripts/install_deps_arch.sh
-
-# openSUSE
-bash scripts/install_deps_opensuse.sh
-
-# Alpine Linux
-bash scripts/install_deps_alpine.sh
-
-# macOS (Homebrew)
-bash scripts/install_deps_macos.sh
-```
-
-For full package lists per platform see `DEPENDENCIES.md`.
-
-Wayland is enabled by default with a stub backend for compatibility. Switch to the real wlroots backend with `-DUSE_WAYLAND_STUB=OFF` (or `--real-wayland` in `scripts/bootstrap.sh`) once dependencies are installed.
-
-## Documentation
-
-- [API Documentation](docs/api.md)
-- [Configuration Guide](docs/configuration.md)
-- [Platform Implementation](docs/platforms.md)
-- [Contributing Guide](CONTRIBUTING.md)
-
-## Installed binary and desktop sessions
-
-- The installed binary is named `srdwm` (a compatibility symlink `SRDWM` is also created in the same directory).
-- Desktop session files are installed so you can pick SRDWM at login:
-  - X11 session: `/usr/local/share/xsessions/srdwm.desktop`
-  - Wayland session: `/usr/local/share/wayland-sessions/srdwm-wayland.desktop`
-- If your display manager (GDM/SDDM/LightDM) doesn’t show them, ensure it reads sessions from `/usr/local/share/*sessions` or adjust your install prefix.
-
-Install options (CMake variables):
-- `-DSRDWM_INSTALL_X11_SESSION=ON|OFF` - install X11 session file (default ON)
-- `-DSRDWM_INSTALL_WAYLAND_SESSION=ON|OFF` - install Wayland session file (default ON)
-
-Example:
-```bash
-cmake -S . -B build -DSRDWM_INSTALL_WAYLAND_SESSION=OFF
-cmake --build build -j
-sudo cmake --install build --prefix /usr/local
-```
-
-## Using SRDWM from another CMake project
-
-After installing SRDWM (e.g., `sudo cmake --install build --prefix /usr/local` on Linux/macOS), you can consume it in another CMake project via `find_package` and link to the exported target.
-
-Minimal example `CMakeLists.txt`:
-
-```cmake
-cmake_minimum_required(VERSION 3.20)
-project(MyApp LANGUAGES CXX)
-
-set(CMAKE_CXX_STANDARD 17)
-set(CMAKE_CXX_STANDARD_REQUIRED ON)
-
-find_package(SRDWM REQUIRED) # provides SRDWM::SRDWM and pulls Lua automatically
-
-add_executable(my_app main.cc)
-target_link_libraries(my_app PRIVATE SRDWM::SRDWM)
-```
-
-Notes:
-- On Linux/macOS, ensure the install prefix (default `/usr/local`) is in CMake’s package search path. You can hint it via `-DCMAKE_PREFIX_PATH=/usr/local` if needed.
-- On Windows with vcpkg, pass your toolchain file when configuring your consumer project:
-  ```powershell
-  cmake -S . -B build -G Ninja -DCMAKE_TOOLCHAIN_FILE="C:/path/to/vcpkg/scripts/buildsystems/vcpkg.cmake"
-  ```
-- The exported package config internally requires Lua (handled by the SRDWM package config).
-
-## Contributing
-
-We welcome contributions! Please see [CONTRIBUTING.md](CONTRIBUTING.md) for details.
-
-### **Development Setup**
-
-```bash
-# Clone with submodules
-git clone --recursive https://github.com/srdusr/srdwm.git
-cd srdwm
-
-# Install development dependencies
-sudo apt install build-essential cmake pkg-config liblua5.3-dev \
-    libx11-dev libxrandr-dev libxinerama-dev libxcb-dev \
-    libxcb-keysyms1-dev libxcb-icccm4-dev libwayland-dev \
-    wayland-protocols libwlroots-dev libgtest-dev
-
-# Build with tests
-mkdir build && cd build
-cmake -DBUILD_TESTS=ON ..
-make -j$(nproc)
-
-# Run tests
-ctest
-```
-
-## Acknowledgments
-
-- **Hyprland** for Wayland compositor inspiration
-- **DWM** for X11 window management concepts
-- **i3** for tiling layout ideas
-- **Windows 11** for smart placement algorithms
-
-## Support
-
-- **Issues**: [GitHub Issues](https://github.com/srdusr/srdwm/issues)
-- **Discussions**: [GitHub Discussions](https://github.com/srdusr/srdwm/discussions)
-- **Wiki**: [GitHub Wiki](https://github.com/srdusr/srdwm/wiki)
-
 ## License
 
-This project is licensed under the MIT License - see the [LICENSE](LICENSE) file for details.
-
+MIT, see [`LICENSE`](LICENSE).