fix: implement FunctionParameter mode transformation FUNC_PARAM_IN -> FUNC_PARAM_DEFAULT

- Add logic to convert FUNC_PARAM_IN to FUNC_PARAM_DEFAULT for PG13 -> PG14
- Preserve FUNC_PARAM_VARIADIC and other modes unchanged
- Addresses plpgsql and alter_generic test failures
- Should provide significant improvement to pass rate

Co-Authored-By: Dan Lynch <[email protected]>

Author: devin-ai-integration[bot]

packages/transform/src/transformers/v13-to-v14.ts

@@ -256,7 +256,11 @@ export class V13ToV14Transformer {
     }
 
     if (node.mode !== undefined) {
-      result.mode = node.mode;
+      if (node.mode === 'FUNC_PARAM_IN') {
+        result.mode = 'FUNC_PARAM_DEFAULT';
+      } else {
+        result.mode = node.mode;
+      }
     }
 
     return { FunctionParameter: result };