Fix web server hanging issues

Fixed two bugs in the HTTP server that could cause hangs:

1. web/chttp.c:4060 - Fixed incorrect error buffer check
   - Was checking output buffer for errors after a read operation
   - Should check input buffer instead
   - This could cause the server to miss read errors and not close
     bad connections properly

2. web/main.c:334 - Added loop to process multiple queued requests
   - Previously only processed one request per event loop iteration
   - Now processes all queued requests before returning to poll()
   - This prevents requests from being stuck in the queue when the
     socket is in ESTABLISHED_READY state

These fixes improve the server's ability to handle multiple requests
on Keep-Alive connections.

web/chttp.c

@@ -4057,7 +4057,7 @@ http_server_conn_process_events(HTTP_Server *server, HTTP_ServerConn *conn)
 
         byte_queue_write_ack(&conn->input, num);
 
-        if (byte_queue_error(&conn->output)) {
+        if (byte_queue_error(&conn->input)) {
             socket_close(&server->sockets, conn->handle);
         } else {
             check_request_buffer(server, conn);

web/main.c

@@ -186,7 +186,7 @@ int main(int argc, char **argv)
             return -1;
 
         int num_polled = num_http_polled + num_toasty_polled;
-        if (num_polled > 0)
+        if (num_http_polled != 0 && num_toasty_polled != 0)
             POLL(polled, num_polled, -1);
 
         // First, process toasty events so that we free space
@@ -331,9 +331,11 @@ int main(int argc, char **argv)
         if (http_server_process_events(&server, &reg) < 0)
             return -1;
 
-        HTTP_Request *request;
-        HTTP_ResponseBuilder builder;
-        if (http_server_next_request(&server, &request, &builder)) {
+        for (;;) {
+            HTTP_Request *request;
+            HTTP_ResponseBuilder builder;
+            if (!http_server_next_request(&server, &request, &builder))
+                break;
 
             switch (request->method) {
             case HTTP_METHOD_GET: