ci: add issue and PR templates with bilingual support

Add GitHub issue templates (bug report, feature request, documentation
issue, question) and PR template. All templates use bilingual format
(English + Chinese) to support the international community.

.github/ISSUE_TEMPLATE/doc_issue.yml

@@ -0,0 +1,60 @@
+name: "Documentation Issue / 文档问题"
+description: |
+  Report documentation errors, outdated content, or missing information.
+  报告文档错误、过时内容或缺失信息。
+labels:
+  - documentation
+body:
+  - type: checkboxes
+    attributes:
+      label: Self Checks / 自检
+      options:
+        - label: |
+            I have searched for [existing issues](https://github.com/farion1231/cc-switch/issues), including closed ones.
+            我已搜索过[已有的 Issue](https://github.com/farion1231/cc-switch/issues)，包括已关闭的。
+          required: true
+
+  - type: dropdown
+    attributes:
+      label: Language / 语言
+      description: |
+        Which language version of the docs?
+        涉及哪个语言版本的文档？
+      multiple: true
+      options:
+        - English
+        - 中文
+        - 日本語
+    validations:
+      required: true
+
+  - type: input
+    attributes:
+      label: Document Location / 文档位置
+      description: |
+        Which file or section is affected? Provide a link or file path.
+        涉及哪个文件或章节？请提供链接或文件路径。
+      placeholder: "e.g. README.md#faq or docs/user-manual/zh/..."
+    validations:
+      required: true
+
+  - type: dropdown
+    attributes:
+      label: Issue Type / 问题类型
+      options:
+        - "Typo or grammar / 拼写或语法错误"
+        - "Outdated content / 内容过时"
+        - "Missing information / 信息缺失"
+        - "Translation issue / 翻译问题"
+        - "Other / 其他"
+    validations:
+      required: true
+
+  - type: textarea
+    attributes:
+      label: Description / 描述
+      description: |
+        Describe the documentation issue.
+        描述文档问题。
+    validations:
+      required: true