Avoid rebuilding byte-identical source graphs

src/lib/compiler.cpp

@@ -497,7 +497,10 @@ SharedUnitFilesystemState inspect_shared_unit_filesystem(Request* context, Share
 		state.current_input_signature != "" &&
 		state.metadata_input_signature == state.current_input_signature
 	);
-	state.required_time = std::max({state.source_time, state.setup_template_time, state.compiler_abi_time});
+	// Source and setup-template freshness is content-addressed by the input
+	// signature. Keep the executable timestamp as the independent codegen
+	// boundary, but do not rebuild byte-identical sources after a touch/restore.
+	state.required_time = state.compiler_abi_time;
 	// Native .so execution has been removed; compile freshness is the wasm
 	// side-module freshness.
 	state.compiled_time = file_mtime(su->wasm_name);