Replace set_position with anchor and offset for relative positioning. Add parent pointer to widget hierarchy. Remove manual resize logic in UI managers.
Remove scale from base Widget class and add per-type set_scale/scale methods to Button, Image, and Label. Dispatch separate WindowResizeEvent alongside existing FrameBufferResizeEvent. Correct centering calculations from `+` to `-` in main menu and world UI managers.
Modify width() and height() methods to multiply by m_scale for both Label and Image. Rename internal dimensions to m_real_width and m_real_height for clarity. Adjust Button foreground position to vertically center when label is scaled.
Replace the plain vertex vector with a TextMesh struct that carries width, height, and min coordinates. Update Label to compute and store these values immediately on text change (removing lazy dirty update). Fix Button's width/height to factor in scale and use concrete widget types for background and foreground.
- Implement MainMenuScene with a "Start Game" button that pushes the WorldScene.
- Extend Button class with background/foreground, hover detection, and size queries.
- Add virtual width/height and event handlers to Widget base class.
- Update WorldUIManager to propagate mouse move events.
- Adjust Window mouse mode based on game running state.
Replace the old `Text` class with a new component-based UI system consisting of `Widget` and `Label` classes. Key changes:
- Remove `Text` class and its GPU upload logic; introduce `Label` as a `Widget` subclass with dirty-flag vertex update.
- Add `UIVertexData` struct to manage per-label vertex buffer/array and memory.
- Refactor `DebugCollector` to store labels in a `Widget` tree, removing hash-based lookup.
- Simplify `Font::vertices()` signature by removing position/scale parameters; scaling is now applied in the renderer’s model matrix.
- Update `Renderer` with `render_label()` and move UI rendering to a `render_ui()` that renders the widget tree.
- Add new source files `label.cpp`, `widget.cpp`, `ui_vertex_data.cpp` and update CMakeLists.
