Re-translate the Japanese version (#1871)

* Retranslate Japanese docs with GPT-5.4

* Retranslate Japanese code with GPT-5.4

ja/codes/kotlin/chapter_dynamic_programming/climbing_stairs_dfs.kt

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+/**
+ * File: climbing_stairs_dfs.kt
+ * Created Time: 2024-01-25
+ * Author: curtishd (1023632660@qq.com)
+ */
+
+package chapter_dynamic_programming
+
+/* 検索 */
+fun dfs(i: Int): Int {
+    // dp[1] と dp[2] は既知なので返す
+    if (i == 1 || i == 2) return i
+    // dp[i] = dp[i-1] + dp[i-2]
+    val count = dfs(i - 1) + dfs(i - 2)
+    return count
+}
+
+/* 階段登り：探索 */
+fun climbingStairsDFS(n: Int): Int {
+    return dfs(n)
+}
+
+/* Driver Code */
+fun main() {
+    val n = 9
+
+    val res = climbingStairsDFS(n)
+    println("$n 段の階段の登り方は全部で $res 通り")
+}