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.

plugins_upper/anthropic/CMakeLists.txt

@@ -0,0 +1,22 @@
+cmake_minimum_required(VERSION 3.21)
+
+# ============================================================
+# plugin-anthropic — Anthropic Claude AI 服务
+# 依赖: http 服务 (查询), config 服务 (查询)
+# ============================================================
+
+add_library(plugin-anthropic SHARED
+    src/anthropic_plugin.cpp
+)
+
+target_link_libraries(plugin-anthropic PRIVATE dstalk)
+
+# Boost.JSON 用于构建/解析请求和响应
+find_package(Boost REQUIRED CONFIG)
+target_link_libraries(plugin-anthropic PRIVATE boost::boost dstalk_boost_config)
+
+set_target_properties(plugin-anthropic PROPERTIES
+    PREFIX ""
+    LIBRARY_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/plugins"
+    RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/plugins"
+)