refactor: remove Java code sections from all LeetCode Hot 100 markdown files

- Remove all "## Java 解法" sections and Java code blocks
- Replace "## Go 解法" with "## 解法"
- Remove "### Go 代码要点" and "### Java 代码要点" sections
- Keep all Go code sections intact
- Maintain complete documentation structure and content
- Update 22 markdown files in the LeetCode Hot 100 directory

16-LeetCode Hot 100/单词搜索.md

@@ -97,49 +97,6 @@ func exist(board [][]byte, word string) bool {
 
 ### Java 实现
 
-```java
-public class Solution {
-    private boolean[][] visited;
-    private int[][] directions = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}};
-
-    public boolean exist(char[][] board, String word) {
-        int m = board.length, n = board[0].length;
-        visited = new boolean[m][n];
-
-        for (int i = 0; i < m; i++) {
-            for (int j = 0; j < n; j++) {
-                if (board[i][j] == word.charAt(0) && dfs(board, word, i, j, 0)) {
-                    return true;
-                }
-            }
-        }
-        return false;
-    }
-
-    private boolean dfs(char[][] board, String word, int i, int j, int k) {
-        if (k == word.length()) {
-            return true;
-        }
-
-        if (i < 0 || i >= board.length || j < 0 || j >= board[0].length ||
-            visited[i][j] || board[i][j] != word.charAt(k)) {
-            return false;
-        }
-
-        visited[i][j] = true;
-
-        for (int[] dir : directions) {
-            if (dfs(board, word, i + dir[0], j + dir[1], k + 1)) {
-                visited[i][j] = false;
-                return true;
-            }
-        }
-
-        visited[i][j] = false;
-        return false;
-    }
-}
-```
 
 ## 复杂度分析