refactor(go)!: 分离练习区与独立项目区

- 将现有练习及 module 文件迁移至 go/practice，保持代码和依赖不变
- 新增 go/projects 项目区说明，更新目录约定与开发命令

BREAKING CHANGE: Go 练习命令需改在 go/practice 目录下执行

go/practice/go.mod

@@ -0,0 +1,43 @@
+module lab
+
+go 1.27.0
+
+require (
+	github.com/gin-contrib/sessions v1.1.2
+	github.com/gin-gonic/gin v1.12.0
+	golang.org/x/crypto v0.56.0
+)
+
+require (
+	github.com/bytedance/gopkg v0.1.4 // indirect
+	github.com/bytedance/sonic v1.15.2 // indirect
+	github.com/bytedance/sonic/loader v0.5.1 // indirect
+	github.com/cloudwego/base64x v0.1.7 // indirect
+	github.com/gabriel-vasile/mimetype v1.4.13 // indirect
+	github.com/gin-contrib/sse v1.1.1 // indirect
+	github.com/go-playground/locales v0.14.1 // indirect
+	github.com/go-playground/universal-translator v0.18.1 // indirect
+	github.com/go-playground/validator/v10 v10.30.3 // indirect
+	github.com/goccy/go-json v0.10.6 // indirect
+	github.com/goccy/go-yaml v1.19.2 // indirect
+	github.com/gorilla/context v1.1.2 // indirect
+	github.com/gorilla/securecookie v1.1.2 // indirect
+	github.com/gorilla/sessions v1.4.0 // indirect
+	github.com/json-iterator/go v1.1.12 // indirect
+	github.com/klauspost/cpuid/v2 v2.4.0 // indirect
+	github.com/leodido/go-urn v1.4.0 // indirect
+	github.com/mattn/go-isatty v0.0.23 // indirect
+	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
+	github.com/modern-go/reflect2 v1.0.2 // indirect
+	github.com/pelletier/go-toml/v2 v2.4.3 // indirect
+	github.com/quic-go/qpack v0.6.0 // indirect
+	github.com/quic-go/quic-go v0.60.0 // indirect
+	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
+	github.com/ugorji/go/codec v1.3.1 // indirect
+	go.mongodb.org/mongo-driver/v2 v2.8.0 // indirect
+	golang.org/x/arch v0.29.0 // indirect
+	golang.org/x/net v0.57.0 // indirect
+	golang.org/x/sys v0.47.0 // indirect
+	golang.org/x/text v0.41.0 // indirect
+	google.golang.org/protobuf v1.36.11 // indirect
+)