feat: add include resolver, dependency graph, BFS scanner (#368)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

src/command/search_config.cpp

@@ -37,6 +37,7 @@ SearchConfig extract_search_config(llvm::ArrayRef<const char*> arguments,
 
     llvm::BumpPtrAllocator allocator;
     ArgumentParser parser{&allocator};
+    parser.set_visibility(default_visibility(arguments[0]));
 
     parser.parse(
         llvm::ArrayRef(arguments).drop_front(),