Leetcode 2267. Check if There Is a Valid Parentheses String Path

Given an m×n grid of '(' and ')', determine whether there exists a down/right path from the top-left to bottom-right whose concatenated characters form a valid parentheses string. The core challenge is exploring paths while tracking a feasible parentheses balance (never negative and zero at the end), typically handled by DP/BFS over positions augmented with balance and aggressive pruning.