initial commit: Go version of SMS Receiver with fixed template rendering

- Implemented all core features from Python version
- Fixed int64/int type compatibility in template functions
- Added login authentication, SMS receiving, statistics, logs
- Independent database: sms_receiver_go.db
- Fixed frontend display issues for message list and statistics

test_api.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+# 测试 Go 版本 API
+
+echo "测试 API /api/messages..."
+curl -s http://127.0.0.1:28001/api/messages | python3 -m json.tool | head -30
+
+echo -e "\n\n测试 API /api/statistics..."
+curl -s http://127.0.0.1:28001/api/statistics | python3 -m json.tool
+
+echo -e "\n\n测试首页 / (先登录获取 cookie)"
+# 这里需要手动登录测试