🐛 fix(tests): report missing toml parser clearly

tests/templates/validate_python_templates.sh

@@ -53,17 +53,21 @@ validate_toml_syntax() {
 
     if python3 << EOF
 import sys
-try:
-    import tomli
-except ImportError:
+parser = None
+for module_name in ("tomli", "tomllib", "toml"):
     try:
-        import tomllib as tomli
+        parser = __import__(module_name)
+        break
     except ImportError:
-        import toml as tomli
+        continue
+
+if parser is None:
+    print("缺少 TOML 解析器（需要 tomli、tomllib 或 toml）", file=sys.stderr)
+    sys.exit(2)
 
 try:
     with open("$file", "rb") as f:
-        tomli.load(f)
+        parser.load(f)
     sys.exit(0)
 except Exception as e:
     print(f"TOML 语法错误: {e}", file=sys.stderr)
@@ -74,8 +78,14 @@ EOF
         VALIDATION_PASSED=$((VALIDATION_PASSED + 1))
         return 0
     else
-        echo "  ❌ $description: TOML 语法错误"
-        echo "TOML 语法错误: $file" >> "$ERRORS_FILE"
+        status=$?
+        if [ "$status" -eq 2 ]; then
+            echo "  ❌ $description: 缺少 TOML 解析器"
+            echo "缺少 TOML 解析器: $file" >> "$ERRORS_FILE"
+        else
+            echo "  ❌ $description: TOML 语法错误"
+            echo "TOML 语法错误: $file" >> "$ERRORS_FILE"
+        fi
         VALIDATION_FAILED=$((VALIDATION_FAILED + 1))
         return 1
     fi