Initial import: robot firmware + PlatformIO two-env scaffold

Robot-side firmware (Teensy 4.0) imported unchanged as extracted.
platformio.ini defines [env:robot] (teensy40) and [env:remote]
(teensy41); scripts/select_src_dir.py points each env at its own
sketch folder so robot/ and remote/ stay Arduino-style sketches.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

2026-current/robot/InputMapper.h

@@ -0,0 +1,30 @@
+#pragma once
+#include "Comms.h"
+#include "GaitEngine.h"
+#include "BodyPose.h"
+
+struct MapperOutput {
+  Twist twist;
+  PoseCommand pose;
+  bool armed = false;
+  bool stand_request = false;
+  bool walk_active = false;
+  bool mode_b = false;
+  bool gait_wave = false;
+  bool remote_gyro_enabled = false;
+  bool robot_gyro_enabled = false;
+};
+
+class InputMapper {
+public:
+  // heading_deg is the robot's current tracked heading estimate; only mode B uses it.
+  MapperOutput map(const CmdPacket& p, float heading_deg, float dt);
+
+private:
+  float heading_target_deg_ = 0;
+  static constexpr float MAX_TURN_RATE_DEG_S = 90.0f;
+  static constexpr float HEADING_KP = 2.0f;
+  static constexpr float MAX_LINEAR_MM_S = 150.0f;   // tune to your leg workspace / servo speed
+  static constexpr float MAX_POSE_OFFSET_MM = 40.0f;
+  static constexpr float MAX_TILT_DEG = 20.0f;
+};