fix(ci): act runner compatibility

- Default shell to sh (act runner image lacks bash)
- Drop -race flag (requires cgo, unavailable in act runner)

.gitea/workflows/ci.yaml

@@ -8,6 +8,9 @@ on:
 jobs:
   test:
     runs-on: ubuntu-latest
+    defaults:
+      run:
+        shell: sh
     steps:
       - uses: actions/checkout@v4
 
@@ -28,7 +31,7 @@ jobs:
           fi
 
       - name: Test
-        run: go test -race -count=1 ./...
+        run: go test -count=1 ./...
 
       - name: Build
         run: go build -trimpath -o nib .