[LordKobra]

Second part of the Wayland backend (split from #121) after #129

Included:

• Keyboard: keymap via xkbcommon, key events with text, key repeat
• Mouse: move, buttons, wheel
• Cursor shapes ( cursor-shape-v1 )
• Mouse-look: pointer lock + relative motion while the cursor is hidden (pointer-constraints , relative-pointer)
• Focus: focus in/out, held keys and buttons released on focus loss, click that focuses the window filtered
• All input goes through app event queue from Wayland basics: window + event loop #129

New required protocols: wl_seat (v8), wp_cursor_shape_manager_v1, zwp_pointer_constraints_v1, zwp_relative_pointer_manager_v1 (all v1).

Not implemented yet: touchpad scrolling, dead keys.