chore: 删除重复的 Issue 模板并增强 .gitignore

- 删除重复的 translation-request.md，保留功能更完整的 translation_request.md

- .gitignore 新增 node_modules/、.env、Python 缓存、虚拟环境和构建输出等常用规则

Author: shijiashuai

.github/ISSUE_TEMPLATE/translation-request.md

@@ -19,6 +19,25 @@ npm-debug.log*
 yarn-debug.log*
 yarn-error.log*
 
+# Dependencies
+node_modules/
+
+# Environment files
+.env
+.env.local
+.env.*.local
+
+# Python
+__pycache__/
+*.py[cod]
+*.pyo
+.venv/
+venv/
+
 # Temporary files
 *.tmp
 *.temp
+
+# Build output
+dist/
+build/