fix(ci): add gcc/musl-dev for race detector in test step

backend/.woodpecker.yml

@@ -12,8 +12,8 @@ steps:
   test:
     image: golang:1.25-alpine
     commands:
-      - apk add --no-cache git
-      - go test ./... -v -count=1 -race
+      - apk add --no-cache git gcc musl-dev
+      - CGO_ENABLED=1 go test ./... -v -count=1 -race
 
   build:
     image: golang:1.25-alpine