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, 226 insertions, 0 deletions

diff --git a/legacy-cpp/Makefile b/legacy-cpp/Makefile
new file mode 100644
index 0000000..d4bdf64
--- /dev/null
+++ b/legacy-cpp/Makefile
@@ -0,0 +1,226 @@
+# SRDWM Makefile
+# Builds the project without requiring cmake
+
+CXX = g++
+CXXFLAGS = -std=c++17 -Wall -Wextra -Wpedantic -fPIC
+INCLUDES = -Isrc -Isrc/core -Isrc/layouts -Isrc/input -Isrc/platform -Isrc/config -Isrc/utils
+
+# Platform detection
+UNAME_S := $(shell uname -s)
+UNAME_M := $(shell uname -m)
+
+# Platform-specific flags and libraries
+ifeq ($(UNAME_S),Linux)
+    PLATFORM = LINUX_PLATFORM
+    CXXFLAGS += -DLINUX_PLATFORM
+    
+    # Check for Wayland support
+    ifeq ($(shell pkg-config --exists wayland-client 2>/dev/null && echo yes),yes)
+        ifeq ($(shell pkg-config --exists wlroots 2>/dev/null && echo yes),yes)
+            CXXFLAGS += -DWAYLAND_ENABLED
+            WAYLAND_LIBS = $(shell pkg-config --libs wayland-client wlroots 2>/dev/null)
+            WAYLAND_CFLAGS = $(shell pkg-config --cflags wayland-client wlroots 2>/dev/null)
+        endif
+    endif
+    
+    # X11 libraries (always available on Linux)
+    X11_LIBS = -lX11 -lXrandr -lXinerama -lXfixes -lXcursor
+    X11_CFLAGS = $(shell pkg-config --cflags x11 xrandr xinerama xfixes xcursor 2>/dev/null || echo "")
+    
+else ifeq ($(UNAME_S),Darwin)
+    PLATFORM = MACOS_PLATFORM
+    CXXFLAGS += -DMACOS_PLATFORM
+    LIBS = -framework Cocoa -framework Carbon -framework IOKit
+    
+else ifeq ($(UNAME_S),MINGW32_NT-10.0)
+    PLATFORM = WIN32_PLATFORM
+    CXXFLAGS += -DWIN32_PLATFORM
+    LIBS = -luser32 -lgdi32 -ldwmapi
+    
+else ifeq ($(UNAME_S),MINGW64_NT-10.0)
+    PLATFORM = WIN32_PLATFORM
+    CXXFLAGS += -DWIN32_PLATFORM
+    LIBS = -luser32 -lgdi32 -ldwmapi
+    
+else ifeq ($(UNAME_S),MSYS_NT-10.0)
+    PLATFORM = WIN32_PLATFORM
+    CXXFLAGS += -DWIN32_PLATFORM
+    LIBS = -luser32 -lgdi32 -ldwmapi
+    
+else
+    PLATFORM = UNKNOWN
+    $(warning Unknown platform: $(UNAME_S))
+endif
+
+# Lua support (optional)
+LUA_AVAILABLE := $(shell ldconfig -p | grep -q liblua5.4 && echo yes)
+ifeq ($(LUA_AVAILABLE),yes)
+    # Check for Lua headers
+    LUA_HEADERS := $(shell find /usr/include -name "lua.h" 2>/dev/null | head -1)
+    ifneq ($(LUA_HEADERS),)
+        CXXFLAGS += -DLUA_ENABLED
+        LUA_LIBS = -llua5.4
+        LUA_CFLAGS = -I$(dir $(LUA_HEADERS))
+        LUA_SOURCES = src/config/lua_manager.cc
+        $(info Lua support enabled)
+    else
+        $(warning Lua runtime found but headers not found - Lua support disabled)
+        LUA_SOURCES = 
+    endif
+else
+    $(warning Lua not found - Lua support disabled)
+    LUA_SOURCES = 
+endif
+
+# Source files
+SOURCES = \
+    src/main.cc \
+    src/core/window.cc \
+    src/core/window_manager.cc \
+    src/layouts/layout_engine.cc \
+    src/layouts/dynamic_layout.cc \
+    src/layouts/tiling_layout.cc \
+    src/layouts/smart_placement.cc \
+    src/platform/platform_factory.cc
+
+# Add Lua sources if available
+ifneq ($(LUA_SOURCES),)
+    SOURCES += $(LUA_SOURCES)
+endif
+
+# Platform-specific source files
+ifeq ($(PLATFORM),LINUX_PLATFORM)
+    SOURCES += src/platform/x11_platform.cc
+    ifeq ($(shell pkg-config --exists wlroots 2>/dev/null && echo yes),yes)
+        SOURCES += src/platform/wayland_platform.cc
+    endif
+else ifeq ($(PLATFORM),WIN32_PLATFORM)
+    SOURCES += src/platform/windows_platform.cc
+else ifeq ($(PLATFORM),MACOS_PLATFORM)
+    SOURCES += src/platform/macos_platform.cc
+endif
+
+# Object files
+OBJECTS = $(SOURCES:.cc=.o)
+
+# Target executable
+TARGET = srdwm
+
+# Default target
+all: $(TARGET)
+
+# Build the executable
+$(TARGET): $(OBJECTS)
+	@echo "Linking $(TARGET)..."
+	$(CXX) $(OBJECTS) -o $(TARGET) $(LIBS) $(X11_LIBS) $(WAYLAND_LIBS) $(LUA_LIBS)
+	@echo "Build complete: $(TARGET)"
+
+# Compile source files
+%.o: %.cc
+	@echo "Compiling $<..."
+	$(CXX) $(CXXFLAGS) $(INCLUDES) $(X11_CFLAGS) $(WAYLAND_CFLAGS) $(LUA_CFLAGS) -c $< -o $@
+
+# Clean build artifacts
+clean:
+	@echo "Cleaning build artifacts..."
+	rm -f $(OBJECTS) $(TARGET)
+	@echo "Clean complete"
+
+# Install (requires sudo)
+install: $(TARGET)
+	@echo "Installing $(TARGET)..."
+	sudo cp $(TARGET) /usr/local/bin/
+	sudo mkdir -p /usr/local/share/srdwm/config
+	sudo cp -r config/* /usr/local/share/srdwm/config/
+	sudo mkdir -p /usr/local/share/srdwm/docs
+	sudo cp docs/*.md /usr/local/share/srdwm/docs/
+	@echo "Installation complete"
+
+# Uninstall (requires sudo)
+uninstall:
+	@echo "Uninstalling $(TARGET)..."
+	sudo rm -f /usr/local/bin/$(TARGET)
+	sudo rm -rf /usr/local/share/srdwm
+	@echo "Uninstallation complete"
+
+# Show build information
+info:
+	@echo "=== SRDWM Build Information ==="
+	@echo "Platform: $(PLATFORM)"
+	@echo "Compiler: $(CXX)"
+	@echo "C++ Standard: C++17"
+	@echo "Architecture: $(UNAME_M)"
+	@echo "Sources: $(words $(SOURCES)) files"
+	@echo "Target: $(TARGET)"
+	@echo "Lua Support: $(if $(LUA_SOURCES),Enabled,Disabled)"
+	@echo "================================"
+
+# Show platform-specific information
+platform-info:
+	@echo "=== Platform Information ==="
+	@echo "Platform: $(PLATFORM)"
+ifeq ($(PLATFORM),LINUX_PLATFORM)
+	@echo "Linux Platform: Enabled"
+	@echo "X11 Support: Enabled"
+ifeq ($(shell pkg-config --exists wlroots 2>/dev/null && echo yes),yes)
+	@echo "Wayland Support: Enabled"
+else
+	@echo "Wayland Support: Disabled (wlroots not found)"
+endif
+else ifeq ($(PLATFORM),WIN32_PLATFORM)
+	@echo "Windows Platform: Enabled"
+else ifeq ($(PLATFORM),MACOS_PLATFORM)
+	@echo "macOS Platform: Enabled"
+endif
+	@echo "============================="
+
+# Dependencies
+deps:
+	@echo "=== Dependencies ==="
+ifeq ($(PLATFORM),LINUX_PLATFORM)
+	@echo "Checking Linux dependencies..."
+	@echo "X11 libraries:"
+	@echo "  - libx11-dev"
+	@echo "  - libxrandr-dev"
+	@echo "  - libxinerama-dev"
+	@echo "  - libxfixes-dev"
+	@echo "  - libxcursor-dev"
+ifeq ($(shell pkg-config --exists wlroots 2>/dev/null && echo yes),yes)
+	@echo "Wayland libraries:"
+	@echo "  - libwayland-dev"
+	@echo "  - libwlroots-dev"
+else
+	@echo "Wayland libraries: Not available"
+endif
+	@echo "Lua: $(if $(LUA_SOURCES),Available,Not available)"
+else ifeq ($(PLATFORM),WIN32_PLATFORM)
+	@echo "Windows dependencies:"
+	@echo "  - MinGW-w64"
+	@echo "  - Lua for Windows"
+else ifeq ($(PLATFORM),MACOS_PLATFORM)
+	@echo "macOS dependencies:"
+	@echo "  - Xcode Command Line Tools"
+	@echo "  - Lua (via Homebrew: brew install lua)"
+endif
+	@echo "==================="
+
+# Help
+help:
+	@echo "=== SRDWM Makefile Help ==="
+	@echo "Available targets:"
+	@echo "  all          - Build the project (default)"
+	@echo "  clean        - Remove build artifacts"
+	@echo "  install      - Install to system (requires sudo)"
+	@echo "  uninstall    - Remove from system (requires sudo)"
+	@echo "  info         - Show build information"
+	@echo "  platform-info - Show platform-specific information"
+	@echo "  deps         - Show dependency information"
+	@echo "  help         - Show this help"
+	@echo ""
+	@echo "Environment variables:"
+	@echo "  CXX          - C++ compiler (default: g++)"
+	@echo "  CXXFLAGS     - Additional compiler flags"
+	@echo "  LIBS         - Additional libraries"
+	@echo "========================"
+
+.PHONY: all clean install uninstall info platform-info deps help