feat: release managed service generation and contract diagnostics

examples/managedService/internal/logic/demo/download.go

@@ -0,0 +1,12 @@
+package demo
+
+import (
+	"context"
+	"git.yuntuo.hk/k2safe/go-omni/httpx"
+	"io"
+	"strings"
+)
+
+func (l *Logic) Download(context.Context) (*httpx.Stream, error) {
+	return &httpx.Stream{Content: io.NopCloser(strings.NewReader("file-content")), Name: "example.txt"}, nil
+}