feat(chat): implement client-server chat messaging

Add protobuf definition for ChatMsg, new packet ID CHAT_MSG (4001), and
handle sending/receiving chat messages on both client and server side.
Wire up UI components (ChatBox, TextField) to allow message input and
display, including a message queue in ClientWorld for thread-safe
processing. Also add default initialization for ChatMessage::time.

include/Cubed/gameplay/chat_message.hpp

@@ -6,6 +6,6 @@ namespace Cubed {
 struct ChatMessage {
     std::string player;
     std::string text;
-    uint64_t time;
+    uint64_t time = 0;
 };
 } // namespace Cubed

include/Cubed/gameplay/client_world.hpp

@@ -2,6 +2,7 @@
 #include "Cubed/audio/audio_engine.hpp"
 #include "Cubed/config.hpp"
 #include "Cubed/gameplay/block.hpp"
+#include "Cubed/gameplay/chat_message.hpp"
 #include "Cubed/gameplay/chunk_pos.hpp"
 #include "Cubed/gameplay/client_chunk.hpp"
 #include "Cubed/gameplay/client_player.hpp"
@@ -102,6 +103,10 @@ public:
     Config& get_config();
     WorldScene& world_scene();
     void set_direct_exit();
+
+    void receive_chat_message(ChatMsg& msg);
+    void send_chat_message(ChatMessage& message);
+
     template <typename Fn>
     void register_ticktimer(std::string_view id, TickType threshold, Fn&& f) {
         m_ticktimers.emplace(
@@ -147,6 +152,7 @@ private:
     tbb::concurrent_queue<std::unique_ptr<ClientChunk>> m_pending_upload_queue;
     tbb::concurrent_queue<ChunkPos> m_dirty_chunk_queue;
     tbb::concurrent_queue<PendingSound> m_pending_sound;
+    tbb::concurrent_queue<ChatMessage> m_message_queue;
 
     std::deque<ChunkPos> m_dirty_queue;
     std::vector<const ChunkRenderSnapshot*> m_render_snapshots;

include/Cubed/gameplay/packet.hpp

@@ -61,6 +61,7 @@ enum class PacketEnum : uint16_t {
     BLOCK_CHANGE_RSP = 3004,
     S2C_CLEAR_ALL_CHUNKS = 3005,
     UPDATE_TIME = 3006,
+    CHAT_MSG = 4001,
     PING = 9001,
     PONG = 9002
 
@@ -121,6 +122,9 @@ template <> constexpr uint16_t get_packet_id<Pong>() {
 template <> constexpr uint16_t get_packet_id<PlayerWaterSound>() {
     return std::to_underlying(PacketEnum::PLAYER_WATER_SOUND);
 }
+template <> constexpr uint16_t get_packet_id<ChatMsg>() {
+    return std::to_underlying(PacketEnum::CHAT_MSG);
+}
 
 template <typename T>
     requires std::derived_from<T, google::protobuf::Message>

include/Cubed/gameplay/server_world.hpp

@@ -80,6 +80,8 @@ public:
     void handle_chunk_req(int task_id, const std::string& uuid, ChunkPos pos);
     void handle_block_change(const BlockChangeReq& req);
 
+    void handle_chat_message(ChatMsg& msg);
+
     int chunk_size() const;
     template <typename Fn>
     void register_timer(std::string_view id, TickType threshold, Fn&& f) {
@@ -189,5 +191,7 @@ private:
         std::atomic<std::shared_ptr<PriorityThreadPool>>& thread_pool,
         int threads);
     void send_server_stop();
+
+    void boardcast_message(const std::string& name, const std::string& message);
 };
 } // namespace Cubed

include/Cubed/scene/world_scene.hpp

@@ -35,6 +35,8 @@ public:
     void set_error(std::string_view error);
     void set_mouse(bool pause);
     void set_chatting(bool chatting);
+    // Not thread safe
+    void handle_chat_message(ChatMessage& message);
 
 private:
     bool handle_mouse_move_event(const MouseMoveEvent& e) override;

include/Cubed/ui/chat_box.hpp

@@ -20,6 +20,8 @@ public:
     ChatBox& set_width(float width);
     ChatBox& set_show_lines(int lines);
     ChatBox& set_spacing(float spacing);
+    ChatBox& clear_input();
+    std::string& get_input_text();
     float width() const override;
     float height() const override;
     void set_d_image(TextureManager& m);

include/Cubed/ui/text_field.hpp

@@ -28,13 +28,14 @@ public:
     TextField& set_auto_scale(bool auto_scale);
     TextField& set_app(App* app);
     TextField& set_typing(bool typing);
+    TextField& clear_input();
     bool handle_mouse_move_event(const MouseMoveEvent& e) override;
     bool handle_mouse_button_event(const MouseButtonEvent& e) override;
     bool handle_text_input_event(const TextInputEvent& e) override;
     bool handle_key_event(const KeyEvent& e) override;
     bool handle_window_resize_event(const WindowResizeEvent& e) override;
     const std::string& input_text() const;
-
+    std::string& input_text();
     template <typename F> TextField& set_on_finish(F&& f) {
         m_on_finished = std::forward<F>(f);
         return *this;

include/Cubed/ui/world_ui_manager.hpp

@@ -21,6 +21,8 @@ public:
 
     void set_chatting(bool chantting);
 
+    void add_chat_message(ChatMessage& message);
+
 private:
     bool handle_key_event(const KeyEvent& e) override;
     WorldScene& m_scene;