🐛 fix(ci): inline gitea workflow bootstrap

remove the pre-checkout dependency on .gitea/ci/prepare_repo.sh
from the root workflows and inline the bootstrap logic instead.

add a regression test for workflow bootstrap ordering and register
it in the tests README.

.gitea/workflows/test.yml

@@ -30,13 +30,55 @@ jobs:
 
     steps:
       - name: 📥 准备仓库
-        env:
-          REPO_NAME: ${{ github.event.repository.name }}
-          TOKEN: ${{ secrets.WORKFLOW }}
-          TARGET_SHA: ${{ github.sha }}
-          TARGET_REF: ${{ github.ref }}
-          TARGET_REF_NAME: ${{ github.ref_name }}
-        run: bash .gitea/ci/prepare_repo.sh
+        run: |
+          set -euo pipefail
+
+          echo "========================================"
+          echo "📥 准备仓库到 WORKSPACE_DIR"
+          echo "========================================"
+
+          REPO_NAME="${{ github.event.repository.name }}"
+          REPO_DIR="${WORKSPACE_DIR}/${REPO_NAME}"
+          TOKEN="${{ secrets.WORKFLOW }}"
+          TARGET_SHA="${{ github.sha }}"
+          TARGET_REF="${{ github.ref }}"
+          TARGET_REF_NAME="${{ github.ref_name }}"
+
+          if [ -n "$TOKEN" ]; then
+            REPO_URL="https://oauth2:${TOKEN}@${GITHUB_SERVER_URL#https://}/${GITHUB_REPOSITORY}.git"
+          else
+            REPO_URL="${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY}.git"
+          fi
+
+          if [ -d "$REPO_DIR" ]; then
+            if [ -d "$REPO_DIR/.git" ]; then
+              cd "$REPO_DIR"
+              git clean -fdx
+              git reset --hard
+              git fetch --all --tags --force --prune --prune-tags
+            else
+              rm -rf "$REPO_DIR"
+            fi
+          fi
+
+          if [ ! -d "$REPO_DIR/.git" ]; then
+            mkdir -p "$WORKSPACE_DIR"
+            git clone "$REPO_URL" "$REPO_DIR"
+          fi
+
+          if git -C "$REPO_DIR" cat-file -e "${TARGET_SHA}^{commit}" 2>/dev/null; then
+            git -C "$REPO_DIR" checkout -f "$TARGET_SHA"
+          else
+            if [ -n "$TARGET_REF" ]; then
+              git -C "$REPO_DIR" fetch origin "$TARGET_REF"
+              git -C "$REPO_DIR" checkout -f FETCH_HEAD
+            else
+              git -C "$REPO_DIR" checkout -f "$TARGET_REF_NAME"
+            fi
+          fi
+
+          git config --global --add safe.directory "$REPO_DIR"
+          echo "REPO_DIR=$REPO_DIR" >> "$GITHUB_ENV"
 
       - name: 🔧 安装测试依赖
         run: |