feat: implement giscus comment

src/types/index.d.ts

@@ -39,11 +39,22 @@ export interface ThemeConfig {
 
   comment: {
     enabled: boolean
+    provider?: 'waline' | 'giscus'
     waline?: {
       serverURL?: string
       emoji?: string[]
       search?: boolean
       imageUploader?: boolean
+    },
+    giscus?: {
+      repo: string
+      repoID: string
+      category: string
+      categoryID: string
+      mapping: 'pathname' | 'url' | 'title'
+      inputPosition: 'top' | 'bottom'
+      lang: Exclude<typeof supportedLangs[number], 'zh-CN'>,
+      loading: 'lazy' | 'embed'
     }
   }