Move Switch OTA launcher sources under ports/switch.

Consolidate the native OTA launcher, bootstrap, and assets into the Switch port tree.

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

@@ -0,0 +1,29 @@
+#ifndef GEN1_OTA_NET_H
+#define GEN1_OTA_NET_H
+
+#include <stddef.h>
+
+#ifdef __cplusplus
+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);
+
+/* Mount romfs (CA bundle) and init libcurl. Call before any HTTPS download. */
+int ota_net_init(void);
+void ota_net_shutdown(void);
+
+/* 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. 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, ota_net_progress_fn progress, void *progress_ud);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif