build(gate): forbid production code from importing authoring tools

The architecture check scans tools/ for duplicate class names and fails
when game/ or content/ references res://tools/. The three tools scripts
drop their global class_name (every caller preloads them), and ADR 0012
records that tools/ depends on the domain only.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

scripts/check_architecture.sh

@@ -38,6 +38,9 @@ source_directories="src tests"
 if [ -d game ]; then
 	source_directories="$source_directories game"
 fi
+if [ -d tools ]; then
+	source_directories="$source_directories tools"
+fi
 
 duplicate_classes="$(
 	rg --no-filename -o \
@@ -57,6 +60,11 @@ if [ -d game ]; then
 	test_imports="$(rg -n 'res://tests/' game --glob '*.gd' || true)"
 	fail_with_matches "production imports test code" "$test_imports"
 
+	tool_imports="$(
+		rg -n 'res://tools/' game content --glob '*.gd' --glob '*.tscn' --glob '*.tres' 		2>/dev/null || true
+	)"
+	fail_with_matches "production imports authoring tools" "$tool_imports"
+
 	poc_references="$(rg -n 'poc_[ab]|POC_[AB]' game --glob '*.gd' --glob '*.tscn' || true)"
 	fail_with_matches "production contains a prototype dependency" "$poc_references"