Add smoke particle emitters with ember sparks and enable 4x MSAA

Replace UV scroll workaround for chimney smoke with proper GL_POINTS
particle system. Smoke particles rise, expand, drift, and fade over
4-7 seconds. One in eight particles spawns as a bright orange/red
ember spark. Enable 4x multisample antialiasing for smoother edges
on player models, fences, and foliage.

src/rendering/renderer.cpp

@@ -995,6 +995,7 @@ void Renderer::renderWorld(game::World* world) {
     if (m2Renderer && camera) {
         auto m2Start = std::chrono::steady_clock::now();
         m2Renderer->render(*camera, view, projection);
+        m2Renderer->renderSmokeParticles(*camera, view, projection);
         auto m2End = std::chrono::steady_clock::now();
         lastM2RenderMs = std::chrono::duration<double, std::milli>(m2End - m2Start).count();
     }