chore(ci): 移除 pr-agent 和 mergify 配置

.github/workflows/pr-agent.yml

@@ -1,28 +0,0 @@
-name: PR Agent
-
-on:
-  pull_request:
-    types: [opened, reopened, synchronize]
-  issue_comment:
-    types: [created, edited]
-
-permissions:
-  contents: read
-  pull-requests: write
-  issues: write
-
-jobs:
-  pr_agent:
-    runs-on: ubuntu-latest
-    name: Run PR Agent
-    if: ${{ github.event.sender.type != 'Bot' }}
-    steps:
-      - name: PR Agent Action
-        id: pragent
-        uses: Codium-ai/pr-agent@main
-        env:
-          OPENAI_KEY: ${{ secrets.OPENAI_KEY }}
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-          github_action_config.auto_review: "true"
-          github_action_config.auto_describe: "true"
-          github_action_config.auto_improve: "false"