feat: generate rust-project.json for LSP

Add a CMake module that writes rust-project.json on every configure so
rust-analyzer can resolve the no-Cargo crate layout, sysroot crates,
and proc-macro attributes without Cargo.

Co-Authored-By: qwen (lmstudio/qwen3.8-27b@q3_k_xl): LSP setup

CMakeLists.txt

@@ -4,6 +4,9 @@ set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
 find_program(RUSTC rustc REQUIRED)
 
+# Generate rust-project.json for rust-analyzer (LSP) support.
+include(cmake/RustLSP.cmake)
+
 set(RUST_MACRO_SOURCE "${CMAKE_CURRENT_SOURCE_DIR}/macros/src/lib.rs")
 set(RUST_MACRO "${CMAKE_CURRENT_BINARY_DIR}/rslibc_macros${CMAKE_SHARED_LIBRARY_SUFFIX}")
 set(RUST_LIBRARY_SOURCE "${CMAKE_CURRENT_SOURCE_DIR}/src/lib.rs")