Scaffold PlatformIO project with Docker-based build, test and flash

- pioarduino platform 55.03.312 (Arduino-ESP32 3.3.x / ESP-IDF 5.5),
  board m5stack-stamps3, M5Cardputer 1.1.1
- native env with Unity for host-side tests
- scripts/ci.sh and scripts/flash.sh run PlatformIO in a container
- version injected from git describe
- boot stub shows name, version and pressed keys
- GPL-3.0 license

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

lib/version/src/version.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#ifndef RORO_VERSION
+#define RORO_VERSION "unknown"
+#endif
+
+namespace roro {
+
+constexpr const char* kProductName = "roro9stack";
+
+// "roro9stack v0.1.0" — used on the boot screen and in About.
+inline const char* versionString() { return RORO_VERSION; }
+
+}  // namespace roro