♻️ refactor(lsp_server): move entrypoints out of named modules

- export Run() from launcher module and add non-module main TU
- apply same pattern to module-based test executables
- migrate utils/string implementation fully into string.cppm and drop string.cpp
- point clangd to linux build compilation database

lsp-server/test/test_semantic/CMakeLists.txt

@@ -17,9 +17,9 @@ endif()
 set(CMAKE_EXPERIMENTAL_CXX_MODULE_DYNDEP 1)
 
 set(SOURCES
+    main.cc
     test_semantic.cppm
     ../../src/utils/string.cppm
-    ../../src/utils/string.cpp
     ../../src/language/symbol/internal/builder.cppm
     ../../src/language/symbol/internal/store.cppm
     ../../src/language/symbol/internal/table.cppm

lsp-server/test/test_semantic/main.cc

@@ -0,0 +1,6 @@
+import lsp.test.semantic.main;
+
+int main(int argc, char** argv)
+{
+    return Run(argc, argv);
+}

lsp-server/test/test_semantic/test_semantic.cppm

@@ -436,7 +436,7 @@ namespace
     }
 }
 
-int main(int argc, char** argv)
+export int Run(int argc, char** argv)
 {
     try
     {