fix(115): resolve direct link via app/chrome/downurl + bind CDN link to client UA

115 deprecated the plain web /files/download endpoint (ordinary cookies no
longer get file_url), breaking 302 playback with 'no file_url'. Switch
Resolve() to the current proapi.115.com/app/chrome/downurl endpoint, which
uses 115's m115 (RSA+XOR) request/response encryption (vendored from the
MIT-licensed SheltonZhu/115driver).

115 CDN links are bound to the User-Agent used to request them, so resolve
with the playback client's own UA (plumbed from the play handler) — the host
can then issue a pure 302 the client fetches directly, preserving true offload.

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

internal/handler/cloud.go

@@ -90,7 +90,7 @@ func cloudPlayHandler(svc *service.Container) gin.HandlerFunc {
 			c.JSON(http.StatusBadRequest, gin.H{"error": "ref required"})
 			return
 		}
-		link, err := svc.StorageCfg.CloudResolve(c.Request.Context(), typ, ref)
+		link, err := svc.StorageCfg.CloudResolve(c.Request.Context(), typ, ref, c.Request.UserAgent())
 		if err != nil {
 			c.JSON(http.StatusBadGateway, gin.H{"error": err.Error()})
 			return