Add verified Joy-Con 2 USB bridge with native mouse support

Implement the standalone USB protocol probe and Bluetooth-backed right Joy-Con bridge with its own persistent virtual pairing identity. Preserve complete ordered native reports, including opaque motion data, and match the console feature set. Relay built-in vibration cues only after genuine source acknowledgement and expose safe BOOTSEL pairing control. Include native capture diagnostics and focused protocol, packet-lifecycle, and cue regressions. Native mouse operation confirmed on Switch with bridge 0.24; private captures and firmware backups remain outside the commit.

tools/switch2_usb_probe/storage.h

@@ -0,0 +1,25 @@
+#pragma once
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Synchronous, main-loop-only API for the single-core probe. Serialize calls.
+// Blobs are opaque, nonempty, and at most 512 bytes. Load requires an exact
+// length match and leaves output unchanged on failure; it never writes flash.
+bool probe_storage_load(uint8_t *output, size_t size);
+
+// Success means an identical blob was already committed, or a replacement was
+// committed and read back. Failure never authorizes a protocol acknowledgement.
+bool probe_storage_save(const uint8_t *data, size_t size);
+
+// Flash-relative offset of the two sectors immediately below profile storage.
+uint32_t probe_storage_offset(void);
+
+#ifdef __cplusplus
+}
+#endif