ci(windows): fix shasum PATH by exporting directly in build step

.github/workflows/ci.yml

@@ -226,10 +226,6 @@ jobs:
           done
           exit 1
 
-      - name: Add Git usr/bin to PATH for shasum
-        run: |
-          echo "C:/Program Files/Git/usr/bin" >> "$GITHUB_PATH"
-
       - name: Setup Node.js
         uses: actions/setup-node@v4
         with:
@@ -276,7 +272,9 @@ jobs:
           pnpm install --frozen-lockfile --ignore-scripts=false --config.engine-strict=false --config.enable-pre-post-scripts=true || pnpm install --frozen-lockfile --ignore-scripts=false --config.engine-strict=false --config.enable-pre-post-scripts=true
 
       - name: Run ${{ matrix.task }} (${{ matrix.runtime }})
-        run: ${{ matrix.command }}
+        run: |
+          export PATH="/c/Program Files/Git/usr/bin:$PATH"
+          ${{ matrix.command }}
 
   checks-macos:
     if: github.event_name == 'pull_request'