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, 214 insertions, 0 deletions

diff --git a/legacy-cpp/src/platform/platform_factory.cc b/legacy-cpp/src/platform/platform_factory.cc
new file mode 100644
index 0000000..ef1981a
--- /dev/null
+++ b/legacy-cpp/src/platform/platform_factory.cc
@@ -0,0 +1,214 @@
+#include "platform_factory.h"
+#include <iostream>
+#include <cstring>
+#include <cstdlib>
+#include <algorithm>
+
+// Platform-specific includes
+#ifdef LINUX_PLATFORM
+    #include "x11_platform.h"
+    #ifdef WAYLAND_ENABLED
+        #include "wayland_platform.h"
+    #endif
+#elif defined(WIN32_PLATFORM)
+    #include "windows_platform.h"
+#elif defined(MACOS_PLATFORM)
+    #include "macos_platform.h"
+#endif
+
+std::unique_ptr<Platform> PlatformFactory::create_platform() {
+    #ifdef _WIN32
+        std::cout << "Creating SRDWindows platform..." << std::endl;
+        return std::make_unique<SRDWindowsPlatform>();
+        
+    #elif defined(__APPLE__)
+        std::cout << "Creating macOS platform..." << std::endl;
+        return std::make_unique<MacOSPlatform>();
+        
+    #else
+        // Linux: detect X11 vs Wayland
+        return detect_linux_platform();
+    #endif
+}
+
+std::unique_ptr<Platform> PlatformFactory::create_platform(const std::string& platform_name) {
+    std::cout << "Creating platform: " << platform_name << std::endl;
+    
+    if (platform_name == "x11" || platform_name == "X11") {
+        #ifdef LINUX_PLATFORM
+            return std::make_unique<X11Platform>();
+        #else
+            std::cerr << "X11 platform not available on this system" << std::endl;
+            return nullptr;
+        #endif
+        
+    } else if (platform_name == "wayland" || platform_name == "Wayland") {
+        #ifdef WAYLAND_ENABLED
+            return std::make_unique<WaylandPlatform>();
+        #else
+            std::cerr << "Wayland platform not available on this system" << std::endl;
+            return nullptr;
+        #endif
+        
+    } else if (platform_name == "windows" || platform_name == "SRDWindows") {
+        #ifdef WIN32_PLATFORM
+            return std::make_unique<SRDWindowsPlatform>();
+        #else
+            std::cerr << "SRDWindows platform not available on this system" << std::endl;
+            return nullptr;
+        #endif
+        
+    } else if (platform_name == "macos" || platform_name == "macOS") {
+        #ifdef MACOS_PLATFORM
+            return std::make_unique<MacOSPlatform>();
+        #else
+            std::cerr << "macOS platform not available on this system" << std::endl;
+            return nullptr;
+        #endif
+        
+    } else {
+        std::cerr << "Unknown platform: " << platform_name << std::endl;
+        std::cerr << "Available platforms: x11, wayland, windows, macos" << std::endl;
+        return nullptr;
+    }
+}
+
+std::unique_ptr<Platform> PlatformFactory::detect_linux_platform() {
+    std::cout << "Detecting Linux platform..." << std::endl;
+    
+    // Check environment variables for Wayland
+    const char* wayland_display = std::getenv("WAYLAND_DISPLAY");
+    const char* xdg_session_type = std::getenv("XDG_SESSION_TYPE");
+    const char* display = std::getenv("DISPLAY");
+    
+    std::cout << "Environment variables:" << std::endl;
+    std::cout << "  WAYLAND_DISPLAY: " << (wayland_display ? wayland_display : "not set") << std::endl;
+    std::cout << "  XDG_SESSION_TYPE: " << (xdg_session_type ? xdg_session_type : "not set") << std::endl;
+    std::cout << "  DISPLAY: " << (display ? display : "not set") << std::endl;
+    
+    // Try Wayland first if environment suggests it
+    if (wayland_display || (xdg_session_type && strcmp(xdg_session_type, "wayland") == 0)) {
+        std::cout << "Wayland environment detected, attempting Wayland initialization..." << std::endl;
+        
+        #ifdef WAYLAND_ENABLED
+            auto wayland_platform = std::make_unique<WaylandPlatform>();
+            if (wayland_platform->initialize()) {
+                std::cout << "✓ Wayland platform initialized successfully" << std::endl;
+                return wayland_platform;
+            } else {
+                std::cout << "✗ Wayland initialization failed, falling back to X11" << std::endl;
+            }
+        #else
+            std::cout << "Wayland support not compiled in, falling back to X11" << std::endl;
+        #endif
+    }
+    
+    // Fall back to X11
+    std::cout << "Attempting X11 initialization..." << std::endl;
+    
+    #ifdef LINUX_PLATFORM
+        auto x11_platform = std::make_unique<X11Platform>();
+        if (x11_platform->initialize()) {
+            std::cout << "✓ X11 platform initialized successfully" << std::endl;
+            return x11_platform;
+        } else {
+            std::cout << "✗ X11 initialization failed" << std::endl;
+        }
+    #else
+        std::cout << "X11 support not compiled in" << std::endl;
+    #endif
+    
+    std::cerr << "Failed to initialize any platform backend" << std::endl;
+    return nullptr;
+}
+
+std::vector<std::string> PlatformFactory::get_available_platforms() {
+    std::vector<std::string> platforms;
+    
+    #ifdef LINUX_PLATFORM
+        platforms.push_back("x11");
+        #ifdef WAYLAND_ENABLED
+            platforms.push_back("wayland");
+        #endif
+    #endif
+    
+    #ifdef WIN32_PLATFORM
+        platforms.push_back("windows");
+    #endif
+    
+    #ifdef MACOS_PLATFORM
+        platforms.push_back("macos");
+    #endif
+    
+    return platforms;
+}
+
+std::string PlatformFactory::get_current_platform() {
+    #ifdef _WIN32
+        return "windows";
+    #elif defined(__APPLE__)
+        return "macos";
+    #else
+        // Check if we're running on Wayland
+        const char* wayland_display = std::getenv("WAYLAND_DISPLAY");
+        const char* xdg_session_type = std::getenv("XDG_SESSION_TYPE");
+        
+        if (wayland_display || (xdg_session_type && strcmp(xdg_session_type, "wayland") == 0)) {
+            return "wayland";
+        } else {
+            return "x11";
+        }
+    #endif
+}
+
+bool PlatformFactory::is_platform_available(const std::string& platform_name) {
+    auto available = get_available_platforms();
+    return std::find(available.begin(), available.end(), platform_name) != available.end();
+}
+
+void PlatformFactory::print_platform_info() {
+    std::cout << "\n=== Platform Information ===" << std::endl;
+    std::cout << "Current platform: " << get_current_platform() << std::endl;
+    
+    auto available = get_available_platforms();
+    std::cout << "Available platforms: ";
+    for (size_t i = 0; i < available.size(); ++i) {
+        if (i > 0) std::cout << ", ";
+        std::cout << available[i];
+    }
+    std::cout << std::endl;
+    
+    std::cout << "Environment variables:" << std::endl;
+    const char* wayland_display = std::getenv("WAYLAND_DISPLAY");
+    const char* xdg_session_type = std::getenv("XDG_SESSION_TYPE");
+    const char* display = std::getenv("DISPLAY");
+    
+    std::cout << "  WAYLAND_DISPLAY: " << (wayland_display ? wayland_display : "not set") << std::endl;
+    std::cout << "  XDG_SESSION_TYPE: " << (xdg_session_type ? xdg_session_type : "not set") << std::endl;
+    std::cout << "  DISPLAY: " << (display ? display : "not set") << std::endl;
+    
+    #ifdef LINUX_PLATFORM
+        std::cout << "Linux platform support: Enabled" << std::endl;
+        #ifdef WAYLAND_ENABLED
+            std::cout << "Wayland support: Enabled" << std::endl;
+        #else
+            std::cout << "Wayland support: Disabled" << std::endl;
+        #endif
+    #else
+        std::cout << "Linux platform support: Disabled" << std::endl;
+    #endif
+    
+    #ifdef WIN32_PLATFORM
+        std::cout << "SRDWindows platform support: Enabled" << std::endl;
+    #else
+        std::cout << "SRDWindows platform support: Disabled" << std::endl;
+    #endif
+    
+    #ifdef MACOS_PLATFORM
+        std::cout << "macOS platform support: Enabled" << std::endl;
+    #else
+        std::cout << "macOS platform support: Disabled" << std::endl;
+    #endif
+    
+    std::cout << "=============================" << std::endl;
+}