Rework page wait again

Further reducing bouncing between page and server for loop polling. If there is
a page, the page polls. If there isn't a page, the server polls. Simpler.

src/http/Client.zig

@@ -523,7 +523,7 @@ const Handles = struct {
 };
 
 // wraps a c.CURL (an easy handle)
-const Handle = struct {
+pub const Handle = struct {
     client: *Client,
     conn: Http.Connection,
     node: Handles.HandleList.Node,