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/button_test.h

@@ -0,0 +1,12 @@
+#pragma once
+#include <stdbool.h>
+#include <stdint.h>
+
+typedef struct {
+    bool armed;
+    uint8_t pressed_samples;
+} probe_button_state;
+
+// Sample at 10 ms intervals. Require a release after reset/unavailability,
+// then two pressed samples. Release/error/not-ready clears output immediately.
+bool probe_button_update(probe_button_state* state, int sample, bool ready);