feat: Implement core Player character with networking, movement, and character selection logic, along with a new pointer shader.

assets/shaders/character_pointer.gdshader

@@ -0,0 +1,8 @@
+shader_type spatial;
+render_mode unshaded, blend_mix, depth_draw_opaque;
+
+uniform vec4 pointer_color : source_color = vec4(0.0, 1.0, 0.0, 1.0);
+
+void fragment() {
+	ALBEDO = pointer_color.rgb;
+	}

assets/shaders/character_pointer.gdshader.uid

@@ -0,0 +1 @@
+uid://kadpokx0uoai