Clone the repo in CI without GitHub-hosted actions

Why: The runner cannot reach github.com, so actions/checkout and setup-node would time out before make test.
Evidence: Go 1.27.1 comes from mirrors.aliyun.com and Node 22.23.3 from npmmirror. Checkout uses the job token and GITHUB_SHA.
Impact: Submodule checkout still requires SUBMODULE_TOKEN. A missing secret fails the job with that message.
Refs: feature/agent-stack-r0-r1
Co-authored-by: Cursor <cursoragent@cursor.com>

.gitea/workflows/ci.yaml

@@ -11,18 +11,34 @@ jobs:
     env:
       GOPROXY: https://goproxy.cn,direct
     steps:
-      - name: Configure submodule auth over HTTPS
-        run: git config --global url."https://weichen:${{ secrets.SUBMODULE_TOKEN }}@git-home.u1680832.nyat.app:30319/".insteadOf "ssh://git@git-ssh.u1680832.nyat.app:31411/"
-      - uses: actions/checkout@v4
-        with:
-          submodules: recursive
-          fetch-depth: 0
-      - uses: actions/setup-go@v5
-        with:
-          go-version: "1.27"
-      - uses: actions/setup-node@v4
-        with:
-          node-version: "22"
+      - name: Checkout
+        env:
+          TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          SUBMODULE_TOKEN: ${{ secrets.SUBMODULE_TOKEN }}
+        run: |
+          set -euo pipefail
+          git init -q
+          git remote add origin "${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY}.git"
+          git -c http.extraheader="AUTHORIZATION: token ${TOKEN}" fetch --depth=1 origin "${GITHUB_SHA}"
+          git checkout -q --detach FETCH_HEAD
+          if [ -z "${SUBMODULE_TOKEN}" ]; then
+            echo "SUBMODULE_TOKEN is not configured" >&2
+            exit 1
+          fi
+          git config --global url."https://weichen:${SUBMODULE_TOKEN}@git-home.u1680832.nyat.app:30319/".insteadOf "ssh://git@git-ssh.u1680832.nyat.app:31411/"
+          git -c fetch.recurseSubmodules=false submodule update --init --recursive
+      - name: Install Go 1.27.1
+        run: |
+          set -euo pipefail
+          curl -fsSL -o "$RUNNER_TEMP/go.tgz" https://mirrors.aliyun.com/golang/go1.27.1.linux-amd64.tar.gz
+          tar -C /usr/local -xzf "$RUNNER_TEMP/go.tgz"
+          ln -sfn /usr/local/go/bin/go /usr/local/bin/go
+          ln -sfn /usr/local/go/bin/gofmt /usr/local/bin/gofmt
+      - name: Install Node 22
+        run: |
+          set -euo pipefail
+          curl -fsSL -o "$RUNNER_TEMP/node.tar.xz" https://npmmirror.com/mirrors/node/v22.23.3/node-v22.23.3-linux-x64.tar.xz
+          tar -C /usr/local --strip-components=1 -xJf "$RUNNER_TEMP/node.tar.xz"
       - name: make test (boundaries, pins, libs, core, backend, frontend, ui, agent-command)
         run: make test
       - name: Build the single binary