feat: add OpenAI-compatible AI provider plugin with SSE streaming support

- Implemented the OpenAI-compatible AI provider plugin, including configuration, chat, and chat_stream functionalities.
- Added support for SSE streaming and tool calls.
- Integrated Boost.JSON for JSON handling.
- Created CMake configuration for the plugin.
- Added error handling and logging throughout the plugin.

dstalk_web/CMakeLists.txt

@@ -0,0 +1,27 @@
+# ============================================================
+# dstalk_web — Web 前端 / Web frontend (Boost.Beast HTTP + SSE)
+# ============================================================
+
+find_package(Boost REQUIRED CONFIG)
+
+add_executable(dstalk_web
+    src/main.cpp
+)
+
+set_target_properties(dstalk_web PROPERTIES
+    RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin
+)
+
+target_compile_features(dstalk_web PRIVATE cxx_std_20)
+
+target_link_libraries(dstalk_web
+    PRIVATE
+        dstalk
+        boost::boost
+        dstalk_boost_config
+)
+
+# Windows: Boost.Asio 需要 Winsock / Boost.Asio requires Winsock
+if(WIN32)
+    target_link_libraries(dstalk_web PRIVATE ws2_32)
+endif()