ci(.github/workflows): 扩展 AI PR Review 触发方式

- 新增 `issue_comment` 和 `workflow_dispatch` 触发入口，支持通过评论或手动指定 PR 运行审查。
- 调整并发键与权限配置，兼容多事件场景并补充 `issues: write`。
- 收紧执行条件，仅在仓库内 PR、手动触发或授权评论指令下执行，并按事件类型动态注入 `PR_NUMBER` 与 `PR_HEAD_SHA`。

.github/workflows/ai-pr-review.yml

@@ -5,18 +5,42 @@ on:
     branches:
       - main
     types: [opened, synchronize, reopened]
+  issue_comment:
+    types: [created]
+  workflow_dispatch:
+    inputs:
+      pr_number:
+        description: 'PR number to review'
+        required: true
+        type: number
 
 permissions:
   contents: read
+  issues: write
   pull-requests: write
 
 concurrency:
-  group: ai-pr-review-${{ github.event.pull_request.number }}
+  group: ai-pr-review-${{ github.event_name == 'issue_comment' && github.event.issue.number || github.event_name == 'workflow_dispatch' && inputs.pr_number || github.event.pull_request.number }}
   cancel-in-progress: true
 
 jobs:
   ai-review:
     name: AI PR Review
+    if: >
+      (
+        github.event_name == 'pull_request' &&
+        github.event.pull_request.head.repo.full_name == github.repository
+      ) ||
+      github.event_name == 'workflow_dispatch' ||
+      (
+        github.event_name == 'issue_comment' &&
+        github.event.issue.pull_request != null &&
+        (
+          contains(github.event.comment.body, '/ai-review') ||
+          contains(github.event.comment.body, '@ai-reviewer review')
+        ) &&
+        contains(fromJSON('["OWNER","MEMBER","COLLABORATOR"]'), github.event.comment.author_association)
+      )
     runs-on: ubuntu-latest
     env:
       OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}
@@ -50,8 +74,8 @@ jobs:
           OPENAI_RETRIES: ${{ vars.OPENAI_RETRIES || '2' }}
           GITHUB_TOKEN: ${{ github.token }}
           GITHUB_REPOSITORY: ${{ github.repository }}
-          PR_NUMBER: ${{ github.event.pull_request.number }}
-          PR_HEAD_SHA: ${{ github.event.pull_request.head.sha }}
+          PR_NUMBER: ${{ github.event_name == 'issue_comment' && github.event.issue.number || github.event_name == 'workflow_dispatch' && inputs.pr_number || github.event.pull_request.number }}
+          PR_HEAD_SHA: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.sha || '' }}
           REVIEW_RULES: .github/ai-review.md,AGENTS.md
           REVIEW_IGNORE: .ai-reviewignore
           REVIEW_SEVERITY_THRESHOLD: P3