refact: update dockerfile

Dockerfile

@@ -7,8 +7,13 @@ WORKDIR /app
 # Copy source code
 COPY . .
 
+ENV GOPROXY=https://goproxy.cn,direct
+ENV GOSUMDB=off
+
+
 # Build binary
-RUN CGO_ENABLED=0 GOOS=linux go build -mod=vendor -o doc_ai ./main.go 
+RUN go mod download && \ 
+    CGO_ENABLED=0 GOOS=linux go build -ldflags="-s -w" -o doc_ai ./main.go 
 
 # Runtime stage
 FROM alpine:latest