Re-translate the Japanese version (#1871)

* Retranslate Japanese docs with GPT-5.4

* Retranslate Japanese code with GPT-5.4

ja/codes/ruby/chapter_backtracking/permutations_i.rb

@@ -0,0 +1,46 @@
+=begin
+File: permutations_i.rb
+Created Time: 2024-05-22
+Author: Xuan Khoa Tu Nguyen (ngxktuzkai2000@gmail.com)
+=end
+
+### バックトラッキング法：全順列 I ###
+def backtrack(state, choices, selected, res)
+  # 状態の長さが要素数に等しければ、解を記録
+  if state.length == choices.length
+    res << state.dup
+    return
+  end
+
+  # すべての選択肢を走査
+  choices.each_with_index do |choice, i|
+    # 枝刈り：要素の重複選択を許可しない
+    unless selected[i]
+      # 試行: 選択を行い、状態を更新
+      selected[i] = true
+      state << choice
+      # 次の選択へ進む
+      backtrack(state, choices, selected, res)
+      # バックトラック：選択を取り消し、前の状態に戻す
+      selected[i] = false
+      state.pop
+    end
+  end
+end
+
+### 全順列 I ###
+def permutations_i(nums)
+  res = []
+  backtrack([], nums, Array.new(nums.length, false), res)
+  res
+end
+
+### Driver Code ###
+if __FILE__ == $0
+  nums = [1, 2, 3]
+
+  res = permutations_i(nums)
+
+  puts "入力配列 nums = #{nums}"
+  puts "すべての順列 res = #{res}"
+end