feat: Add LSP plugin unit tests and frontend common initialization library

- Introduced `dstalk_lsp_plugin_test` for testing LSP plugin functionalities including `lsp_trim`, `lsp_frame_message`, and `lsp_parse_content_length`.
- Created `dstalk_frontend_common` static library to encapsulate shared initialization logic for frontend components (CLI, GUI, Web).
- Implemented configuration file discovery and service querying in `dstalk_frontend_init`.
- Added internal headers for LSP and Anthropic plugins to facilitate unit testing.
- Established a mailroom system for asynchronous message passing between stateless agents, enhancing coordination and context management.

tests/CMakeLists.txt

@@ -212,6 +212,40 @@ target_link_libraries(dstalk_network_plugin_test
 
 add_test(NAME dstalk_network_plugin_test COMMAND dstalk_network_plugin_test)
 
+# ============================================================
+# dstalk_lsp_plugin_test — LSP 插件单元测试 (GoogleTest, 新增)
+# 覆盖: lsp_trim / lsp_frame_message / lsp_parse_content_length
+# ============================================================
+
+add_executable(dstalk_lsp_plugin_test
+    lsp_plugin_test.cpp
+    ${CMAKE_SOURCE_DIR}/plugins_base/lsp/src/lsp_plugin.cpp
+)
+
+target_include_directories(dstalk_lsp_plugin_test
+    PRIVATE
+        ${CMAKE_SOURCE_DIR}/dstalk_core/include
+        ${CMAKE_SOURCE_DIR}/plugins_base/lsp/src
+)
+
+target_compile_definitions(dstalk_lsp_plugin_test
+    PRIVATE
+        BOOST_JSON_HEADER_ONLY
+        BOOST_ALL_NO_LIB
+)
+
+target_compile_features(dstalk_lsp_plugin_test
+    PRIVATE cxx_std_17
+)
+
+target_link_libraries(dstalk_lsp_plugin_test
+    PRIVATE
+        dstalk
+        boost::boost
+)
+
+add_test(NAME dstalk_lsp_plugin_test COMMAND dstalk_lsp_plugin_test)
+
 # ============================================================
 # coverage — gcovr 覆盖率报告 (HTML + 终端摘要)
 # 用法: cmake --build <dir> --target coverage