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, 0 insertions, 49 deletions

diff --git a/src/core/window.h b/src/core/window.h
deleted file mode 100644
index 6d7405a..0000000
--- a/src/core/window.h
+++ /dev/null
@@ -1,49 +0,0 @@
-#ifndef WINDOW_H
-#define WINDOW_H
-
-#include <string>
-
-class SRDWindow {
-public:
-    // Constructor
-    SRDWindow(int id, const std::string& title);
-
-    // Getters
-    int getId() const;
-    const std::string& getTitle() const;
-    int getX() const;
-    int getY() const;
-    int getWidth() const;
-    int getHeight() const;
-    bool isDecorated() const;
-
-    // Setters
-    void setTitle(const std::string& title);
-    void setPosition(int x, int y);
-    void setSize(int width, int height);
-    void setGeometry(int x, int y, int width, int height);
-    void setDimensions(int x, int y, int width, int height);
-    void setDecorated(bool decorated);
-    void setId(int id);
-
-    // Window management methods
-    void map();
-    void unmap();
-    void focus();
-    void close();
-
-    // Comparison operators for use in containers
-    bool operator<(const SRDWindow& other) const { return id_ < other.id_; }
-    bool operator==(const SRDWindow& other) const { return id_ == other.id_; }
-
-private:
-    int id_;
-    std::string title_;
-    int x_;
-    int y_;
-    int width_;
-    int height_;
-    bool decorated_;
-};
-
-#endif // WINDOW_H