feat: ✨ add SOCKS5 proxy support and enhance configuration

- Introduced SOCKS5 proxy functionality with separate ports for random rotation and lowest latency.
- Updated `.env.example` and `docker-compose.yml` to include SOCKS5 port configurations.
- Enhanced `main.go` to initialize and start SOCKS5 servers alongside existing HTTP proxies.
- Revised README to document new SOCKS5 features, including usage examples and testing scripts.
- Improved proxy selection logic in the storage layer to support SOCKS5 protocol.

test/test_socks5.sh

@@ -0,0 +1,75 @@
+#!/bin/bash
+###
+ # @LastEditTime: 2026-03-29 23:26:29
+ # @Description: ...
+ # @Date: 2026-03-29 23:14:32
+ # @Author: isboyjc
+ # @LastEditors: isboyjc
+### 
+
+# GoProxy SOCKS5 代理测试脚本
+# 用法: ./test_socks5.sh [端口号，默认7779]
+
+PROXY_HOST="${PROXY_HOST:-127.0.0.1}"
+PROXY_PORT="${1:-7779}"
+TEST_URL="https://httpbin.org/ip"
+DELAY=1
+
+# 统计变量
+total=0
+success=0
+fail=0
+
+# 获取毫秒时间戳（兼容 macOS 和 Linux）
+get_ms_time() {
+    python3 -c 'import time; print(int(time.time() * 1000))'
+}
+
+# 国家代码转 emoji 旗帜
+country_to_emoji() {
+    local country_code="$1"
+    if [ -z "$country_code" ] || [ "$country_code" = "null" ]; then
+        echo "🌐"
+        return
+    fi
+    
+    local first="${country_code:0:1}"
+    local second="${country_code:1:1}"
+    python3 -c "print(chr(127462 + ord('$first') - ord('A')) + chr(127462 + ord('$second') - ord('A')))"
+}
+
+# 捕获 Ctrl+C 信号
+trap ctrl_c INT
+function ctrl_c() {
+    echo ""
+    echo "---"
+    loss_rate=$(awk "BEGIN {printf \"%.1f\", ($total - $success)/$total*100}")
+    echo "$total requests transmitted, $success received, $((total - success)) failed, ${loss_rate}% packet loss"
+    exit 0
+}
+
+echo "SOCKS5 PROXY ${PROXY_HOST}:${PROXY_PORT}: continuous mode"
+echo ""
+
+while true; do
+    total=$((total + 1))
+    
+    # 使用 curl 的 SOCKS5 支持（-k 跳过 SSL 验证，因为免费代理证书常有问题）
+    start=$(get_ms_time)
+    response=$(curl -s -k --socks5-hostname ${PROXY_HOST}:${PROXY_PORT} ${TEST_URL} --max-time 10 2>&1)
+    end=$(get_ms_time)
+    latency=$((end - start))
+    
+    if echo "$response" | grep -q '"origin"'; then
+        success=$((success + 1))
+        origin=$(echo "$response" | grep -o '"origin":"[^"]*"' | cut -d'"' -f4 | cut -d',' -f1)
+        country=$(curl -s "http://ip-api.com/json/${origin}?fields=countryCode" 2>/dev/null | grep -o '"countryCode":"[^"]*"' | cut -d'"' -f4)
+        emoji=$(country_to_emoji "$country")
+        echo "socks5 #${total}: ${origin} ${emoji} ${country} (${latency}ms)"
+    else
+        fail=$((fail + 1))
+        echo "socks5 #${total}: request failed"
+    fi
+    
+    sleep $DELAY
+done