chore: initial commit of ai site platform

Co-authored-by: Cursor <cursoragent@cursor.com>

platform/internal/license/middleware.go

@@ -0,0 +1,44 @@
+package license
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+	"time"
+)
+
+// Middleware 按租约文件判断是否过期。授权控制接口始终放行，便于过期后远端续费/延期。
+func Middleware(m *Manager) func(http.HandlerFunc) http.HandlerFunc {
+	return func(next http.HandlerFunc) http.HandlerFunc {
+		return func(w http.ResponseWriter, r *http.Request) {
+			path := r.URL.Path
+			if isLicenseControlPath(path) || isHealthPath(path) {
+				next(w, r)
+				return
+			}
+			if m == nil || !m.Enabled() {
+				next(w, r)
+				return
+			}
+			st := m.Status(time.Now())
+			if !st.Expired {
+				next(w, r)
+				return
+			}
+			w.Header().Set("Content-Type", "application/json; charset=utf-8")
+			w.WriteHeader(http.StatusPaymentRequired)
+			_, _ = w.Write([]byte(fmt.Sprintf(
+				`{"error":%q,"code":"license_expired","extensions_remaining":%d}`,
+				st.Message, st.ExtensionsRemaining,
+			)))
+		}
+	}
+}
+
+func isHealthPath(path string) bool {
+	return path == "/ping" || path == "/healthz" || strings.HasSuffix(path, "/healthz")
+}
+
+func isLicenseControlPath(path string) bool {
+	return strings.HasPrefix(path, "/api/v1/license/")
+}