move semantic declarations into focused partitions and add new type_system.types/graph.types modules.
reorder lsp server members so async executor shuts down before manager hub to avoid exit crash.
- 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
csh