Improve Switch OTA flow with download progress and clearer error screens.

native/switch-ota-launcher/include/ota_net.h

@@ -7,13 +7,16 @@
 extern "C" {
 #endif
 
+/* fraction is 0..1 when Content-Length is known, else -1 for indeterminate. */
+typedef void (*ota_net_progress_fn)(void *userdata, double fraction);
+
 /* Download URL into memory buffer (caller frees *out). Returns 0 on success. */
 int ota_net_download_buffer(const char *url, long timeout_ms, char **out, size_t *out_len,
                             char *err, size_t err_len);
 
-/* Download URL to a filesystem path. Returns 0 on success. */
+/* Download URL to a filesystem path. progress may be NULL. Returns 0 on success. */
 int ota_net_download_file(const char *url, const char *path, long timeout_ms, char *err,
-                          size_t err_len);
+                          size_t err_len, ota_net_progress_fn progress, void *progress_ud);
 
 #ifdef __cplusplus
 }

native/switch-ota-launcher/include/ota_ui.h

@@ -20,6 +20,10 @@ void ota_ui_show_progress(const char *title, const char *detail, float progress0
 /* Error / info + wait for B. */
 void ota_ui_alert(const char *title, const char *line1, const char *line2);
 
+/* User-friendly error with optional technical detail and installed-version footer. */
+void ota_ui_alert_error(const char *title, const char *friendly, const char *technical,
+                        const char *installed_version);
+
 /* Missing game install screen; wait for +. */
 void ota_ui_missing_game(void);