refactor: config (#30)

* refactor(config): replace singleton with dependency injection

* refactor(client_player): return ChunkPosSet by value in non-const getter

Copy the internal set under the mutex lock to avoid exposing a mutable reference that could be used unsafely after the lock is released. This fixes a potential data race when the caller holds the returned reference beyond the critical section. Also update the caller in `client_world` to remove the now-unnecessary `std::move`.

* fix(gameplay): prevent use-after-free in pending delete queues during destruction

* refactor(config): separate game and server configuration with explicit paths

src/render/renderer.cpp

@@ -20,10 +20,11 @@
 namespace Cubed {
 
 Renderer::Renderer(const Camera& camera, ClientWorld& world,
-                   const TextureManager& texture_manager, DevPanel& dev_panel)
+                   const TextureManager& texture_manager, DevPanel& dev_panel,
+                   Config& config)
     : m_camera(camera), m_dev_panel(dev_panel),
       m_texture_manager(texture_manager), m_world(world),
-      m_world_renderer(*this) {}
+      m_world_renderer(*this), m_config(config) {}
 
 Renderer::~Renderer() {
     if (m_init) {
@@ -38,10 +39,7 @@ Renderer::~Renderer() {
     }
 }
 
-void Renderer::hot_reload() {
-    auto& config = Config::get();
-    update_fov(config.get<double>("player.fov"));
-}
+void Renderer::hot_reload() { update_fov(m_config.get("player.fov", 70.0f)); }
 
 void Renderer::init(bool debug_on) {
     if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {