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-core/CMakeLists.txt

@@ -0,0 +1,41 @@
+# ============================================================
+# dstalk-core — 核心 DLL
+# 包含: 网络通讯 / AI接口 / 文件读写
+# ============================================================
+
+find_package(Boost CONFIG REQUIRED)
+find_package(OpenSSL CONFIG REQUIRED)
+
+add_library(dstalk SHARED
+    src/api.cpp
+    src/file/file_io.cpp
+    src/net/http_client.cpp
+    src/ai/deepseek_api.cpp
+)
+
+target_include_directories(dstalk
+    PUBLIC include
+    PRIVATE src
+)
+
+target_link_libraries(dstalk
+    PRIVATE
+        Boost::boost
+        Boost::system
+        Boost::json
+        OpenSSL::SSL
+        OpenSSL::Crypto
+)
+
+# 导出 DLL 符号宏
+target_compile_definitions(dstalk
+    PRIVATE DSTALK_BUILD_DLL
+    INTERFACE DSTALK_USE_DLL
+)
+
+# Windows: 生成 .lib 导入库和 .dll
+if(WIN32)
+    set_target_properties(dstalk PROPERTIES
+        WINDOWS_EXPORT_ALL_SYMBOLS ON
+    )
+endif()