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, 174 insertions, 0 deletions

diff --git a/legacy-cpp/tests/test_platform_factory.cc b/legacy-cpp/tests/test_platform_factory.cc
new file mode 100644
index 0000000..364b193
--- /dev/null
+++ b/legacy-cpp/tests/test_platform_factory.cc
@@ -0,0 +1,174 @@
+#include <gtest/gtest.h>
+#include "../src/platform/platform_factory.h"
+#include "../src/platform/platform.h"
+
+class PlatformFactoryTest : public ::testing::Test {
+protected:
+    void SetUp() override {
+        // Set up test environment
+    }
+};
+
+TEST_F(PlatformFactoryTest, PlatformDetection) {
+    auto platform = PlatformFactory::create_platform();
+    
+    // Should create a valid platform
+    EXPECT_NE(platform, nullptr);
+}
+
+TEST_F(PlatformFactoryTest, PlatformCreation) {
+    auto platform = PlatformFactory::create_platform();
+    
+    EXPECT_NE(platform, nullptr);
+    EXPECT_TRUE(platform->initialize());
+}
+
+TEST_F(PlatformFactoryTest, PlatformName) {
+    auto platform = PlatformFactory::create_platform();
+    
+    std::string name = platform->get_platform_name();
+    EXPECT_FALSE(name.empty());
+    
+    // Should be one of the expected platform names
+    EXPECT_TRUE(name == "X11" || name == "Wayland" || name == "Windows" || name == "macOS");
+}
+
+TEST_F(PlatformFactoryTest, PlatformCapabilities) {
+    auto platform = PlatformFactory::create_platform();
+    
+    // Test platform-specific capabilities
+    if (platform->is_x11()) {
+        EXPECT_TRUE(platform->get_platform_name() == "X11");
+        EXPECT_FALSE(platform->is_wayland());
+        EXPECT_FALSE(platform->is_windows());
+        EXPECT_FALSE(platform->is_macos());
+    } else if (platform->is_wayland()) {
+        EXPECT_TRUE(platform->get_platform_name() == "Wayland");
+        EXPECT_FALSE(platform->is_x11());
+        EXPECT_FALSE(platform->is_windows());
+        EXPECT_FALSE(platform->is_macos());
+    } else if (platform->is_windows()) {
+        EXPECT_TRUE(platform->get_platform_name() == "Windows");
+        EXPECT_FALSE(platform->is_x11());
+        EXPECT_FALSE(platform->is_wayland());
+        EXPECT_FALSE(platform->is_macos());
+    } else if (platform->is_macos()) {
+        EXPECT_TRUE(platform->get_platform_name() == "macOS");
+        EXPECT_FALSE(platform->is_x11());
+        EXPECT_FALSE(platform->is_wayland());
+        EXPECT_FALSE(platform->is_windows());
+    }
+}
+
+TEST_F(PlatformFactoryTest, MonitorDetection) {
+    auto platform = PlatformFactory::create_platform();
+    
+    auto monitors = platform->get_monitors();
+    EXPECT_FALSE(monitors.empty());
+    
+    for (const auto& monitor : monitors) {
+        EXPECT_GT(monitor.id, 0);
+        EXPECT_FALSE(monitor.name.empty());
+        EXPECT_GT(monitor.width, 0);
+        EXPECT_GT(monitor.height, 0);
+        EXPECT_GT(monitor.refresh_rate, 0);
+    }
+}
+
+TEST_F(PlatformFactoryTest, EventPolling) {
+    auto platform = PlatformFactory::create_platform();
+    
+    std::vector<Event> events;
+    bool result = platform->poll_events(events);
+    
+    // Should not crash, even if no events are available
+    EXPECT_TRUE(result || events.empty());
+}
+
+TEST_F(PlatformFactoryTest, WindowCreation) {
+    auto platform = PlatformFactory::create_platform();
+    
+    auto window = platform->create_window("Test Window", 100, 100, 400, 300);
+    EXPECT_NE(window, nullptr);
+    
+    if (window) {
+        EXPECT_EQ(window->getTitle(), "Test Window");
+        EXPECT_EQ(window->getX(), 100);
+        EXPECT_EQ(window->getY(), 100);
+        EXPECT_EQ(window->getWidth(), 400);
+        EXPECT_EQ(window->getHeight(), 300);
+    }
+}
+
+TEST_F(PlatformFactoryTest, WindowManagement) {
+    auto platform = PlatformFactory::create_platform();
+    
+    auto window = platform->create_window("Test Window", 100, 100, 400, 300);
+    EXPECT_NE(window, nullptr);
+    
+    if (window) {
+        // Test window positioning
+        platform->set_window_position(window.get(), 200, 200);
+        EXPECT_EQ(window->getX(), 200);
+        EXPECT_EQ(window->getY(), 200);
+        
+        // Test window sizing
+        platform->set_window_size(window.get(), 500, 400);
+        EXPECT_EQ(window->getWidth(), 500);
+        EXPECT_EQ(window->getHeight(), 400);
+        
+        // Test window focusing
+        platform->focus_window(window.get());
+        
+        // Test window destruction
+        platform->destroy_window(window.get());
+    }
+}
+
+TEST_F(PlatformFactoryTest, DecorationControls) {
+    auto platform = PlatformFactory::create_platform();
+    
+    auto window = platform->create_window("Test Window", 100, 100, 400, 300);
+    EXPECT_NE(window, nullptr);
+    
+    if (window) {
+        // Test decoration toggling
+        platform->set_window_decorations(window.get(), true);
+        EXPECT_TRUE(platform->get_window_decorations(window.get()));
+        
+        platform->set_window_decorations(window.get(), false);
+        EXPECT_FALSE(platform->get_window_decorations(window.get()));
+        
+        // Test border color
+        platform->set_window_border_color(window.get(), 255, 0, 0);
+        
+        // Test border width
+        platform->set_window_border_width(window.get(), 5);
+        
+        platform->destroy_window(window.get());
+    }
+}
+
+TEST_F(PlatformFactoryTest, InputHandling) {
+    auto platform = PlatformFactory::create_platform();
+    
+    // Test keyboard grabbing
+    platform->grab_keyboard();
+    platform->ungrab_keyboard();
+    
+    // Test pointer grabbing
+    platform->grab_pointer();
+    platform->ungrab_pointer();
+}
+
+TEST_F(PlatformFactoryTest, PlatformShutdown) {
+    auto platform = PlatformFactory::create_platform();
+    
+    // Should not crash on shutdown
+    platform->shutdown();
+}
+
+int main(int argc, char **argv) {
+    ::testing::InitGoogleTest(&argc, argv);
+    return RUN_ALL_TESTS();
+}