Keep real staged compile errors navigable under warning floods

include/faset/editor/build_diagnostics.hpp

@@ -7,9 +7,10 @@
 namespace faset::editor {
 
 // Parse compiler, MSVC/clang-cl and Lua output into bounded Editor-facing rows.
-// Only sources under the current project's Scripts directory receive a file
-// key, so clients cannot offer navigation to unrelated filesystem paths.
+// Only sources under the project Scripts directory or the verified immutable
+// Scripts snapshot supplied by BuildService receive a project-relative file key.
 Json parse_build_diagnostics(std::string_view raw_log, std::string_view phase,
-                             const std::filesystem::path& project_root);
+                             const std::filesystem::path& project_root,
+                             const std::filesystem::path& snapshot_scripts = {});
 
 } // namespace faset::editor