vRIO: virtual RIO cockpit device emulator

Speaks the device side of the RIO serial protocol (per riojoy's
PROTOCOL.md) on a COM port, behind an interactive replica of the
profile editor's cockpit panel: click cells to press buttons/keys,
drag the encoder gauges to move the five analog axes, and watch
host-commanded lamp states (incl. flash modes) light the cells.

Device behavior grounded in the real v4.2 firmware dump: version 4.2,
4-retry NAK budget ending in RESTART, and an optional emulation of the
analog reply-wedge latch leak for exercising host recovery watchdogs.

Verified: 33 unit tests, plus an interop harness driving RIOJoy's
actual RioSerialLink against VRioDevice over an in-memory transport
(version/check/analog/lamp/button/keypad/reset all round-trip).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,11 @@
+# Build output
+[Bb]in/
+[Oo]bj/
+
+# IDE state
+.vs/
+*.user
+*.suo
+
+# Test results
+TestResults/