fix: enable CGO and install OpenCV for docker build

Dockerfile

@@ -1,19 +1,32 @@
 # 构建阶段
 FROM golang:1.22-alpine AS builder
 
+# 安装 OpenCV 和编译工具
+RUN apk add --no-cache \
+    gcc \
+    g++ \
+    musl-dev \
+    opencv-dev \
+    pkgconfig
+
 WORKDIR /app
 
 # 复制源代码
 COPY . .
 
-# 构建
+# 构建 (启用 CGO)
 RUN go mod download || true
-RUN CGO_ENABLED=0 GOOS=linux go build -ldflags="-s -w" -o anticaptcha ./cmd/server
+RUN CGO_ENABLED=1 GOOS=linux go build -ldflags="-s -w" -o anticaptcha ./cmd/server
 
 # 运行阶段
 FROM alpine:3.20
 
-RUN apk add --no-cache ca-certificates tzdata
+# 安装运行时依赖
+RUN apk add --no-cache \
+    ca-certificates \
+    tzdata \
+    opencv-libs \
+    libstdc++
 
 WORKDIR /app
 
@@ -29,4 +42,4 @@ ENV TZ=Asia/Shanghai
 
 EXPOSE 6688
 
-CMD ["./anticaptcha"]
+CMD ["./anticaptcha"]