Initial dstalk project: core DLL + CLI + BearSSL TLS

- Core DLL: AI API client (DeepSeek/OpenAI compatible), HTTP(S) via Boost.Beast
- BearSSL vendored as TLS backend (MIT license, replacing OpenSSL)
- CLI frontend with ANSI colors, /help /model /file /save /load commands
- WinHTTP alternative HTTP client for Windows
- GPLv3 license with linking exception
- Build: CMake + Ninja + Clang, dependencies via Conan2

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

dstalk-gui/CMakeLists.txt

@@ -0,0 +1,15 @@
+# ============================================================
+# dstalk-gui — 图形化前端 (SDL3)
+# ============================================================
+
+find_package(SDL3 REQUIRED)
+
+add_executable(dstalk-gui
+    src/main.cpp
+)
+
+target_link_libraries(dstalk-gui
+    PRIVATE
+        dstalk
+        SDL3::SDL3
+)

dstalk-gui/src/main.cpp

@@ -0,0 +1,57 @@
+#include <cstdio>
+#include <cstdlib>
+
+#include <SDL3/SDL.h>
+
+#include "dstalk/dstalk_api.h"
+
+int main(int argc, char* argv[])
+{
+    if (dstalk_init(nullptr) != 0) {
+        std::fprintf(stderr, "[dstalk] 初始化失败\n");
+        return 1;
+    }
+
+    if (!SDL_Init(SDL_INIT_VIDEO)) {
+        std::fprintf(stderr, "[dstalk] SDL 初始化失败: %s\n", SDL_GetError());
+        dstalk_destroy();
+        return 1;
+    }
+
+    SDL_Window* window = SDL_CreateWindow(
+        "dstalk", 1024, 768, SDL_WINDOW_RESIZABLE);
+    if (!window) {
+        std::fprintf(stderr, "[dstalk] 窗口创建失败: %s\n", SDL_GetError());
+        SDL_Quit();
+        dstalk_destroy();
+        return 1;
+    }
+
+    SDL_Renderer* renderer = SDL_CreateRenderer(window, nullptr);
+    if (!renderer) {
+        SDL_DestroyWindow(window);
+        SDL_Quit();
+        dstalk_destroy();
+        return 1;
+    }
+
+    /* TODO: 主循环 — SDL 事件处理, UI 渲染, 调用 dstalk_chat */
+    bool running = true;
+    SDL_Event event;
+    while (running) {
+        while (SDL_PollEvent(&event)) {
+            if (event.type == SDL_EVENT_QUIT) {
+                running = false;
+            }
+        }
+        SDL_SetRenderDrawColor(renderer, 0x1E, 0x1E, 0x2E, 0xFF);
+        SDL_RenderClear(renderer);
+        SDL_RenderPresent(renderer);
+    }
+
+    SDL_DestroyRenderer(renderer);
+    SDL_DestroyWindow(window);
+    SDL_Quit();
+    dstalk_destroy();
+    return 0;
+}