Add authenticated WebSocket serial terminal - dirty commit with front-

and backend issues

src/web_ui.h

@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-3.0-only */
+/* Offline browser UI response helpers for authenticated HTTPS routes. */
+
+#pragma once
+
+#include "esp_err.h"
+#include "esp_http_server.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef enum {
+    WEB_UI_RESOURCE_INDEX = 0,
+    WEB_UI_RESOURCE_XTERM_JS,
+    WEB_UI_RESOURCE_XTERM_CSS,
+    WEB_UI_RESOURCE_ADDON_FIT_JS,
+    WEB_UI_RESOURCE_APP_JS,
+} web_ui_resource_t;
+
+/*
+ * Send one UI resource after the caller has authenticated the request.
+ * This module deliberately performs no authentication or URI dispatch.
+ */
+esp_err_t web_ui_send_response(httpd_req_t *request,
+                               web_ui_resource_t resource);
+
+#ifdef __cplusplus
+}
+#endif