fix(files): rewrite viewUrl host to API base on download

resolveAPIURL now rewrites absolute viewUrl hosts to the configured portal
base so downloads stay on the internal network and keep the Authorization
header (a cross-host HTTP->HTTPS redirect would otherwise strip it, failing
large-file reads).

files.go

@@ -319,8 +319,18 @@ func (c *Client) resolveAPIURL(ref string) string {
 	if ref == "" {
 		return ref
 	}
-	if strings.HasPrefix(ref, "http://") || strings.HasPrefix(ref, "https://") {
+	// Rewrite any host to the configured API base so downloads stay on the
-		return ref
+	// internal network and keep the Authorization header (no cross-host
+	// redirect that would strip it). Scheme-relative URLs are handled too.
+	if strings.HasPrefix(ref, "//") {
+		ref = "http:" + ref
+	}
+	if u, err := url.Parse(ref); err == nil && u.IsAbs() {
+		if base, err2 := url.Parse(c.baseURL()); err2 == nil {
+			u.Scheme = base.Scheme
+			u.Host = base.Host
+			return u.String()
+		}
 	}
 	base := c.baseURL()
 	if strings.HasPrefix(ref, "/") {