Robot: Teensy 3.6 with the old robot's servo wiring and calibration

- LEGACY/Hexapod_Teensy/: old robot sketch (reference only).
- platformio.ini: robot env targets teensy36 (owner-confirmed board).
- Config.h: per-servo SERVOS table (pin, pulse at 0 deg, signed
  us/deg, pulse limits) built from the old sketch's pins, ranges, trims
  and the old Unity servo directions. Rear-left/front-left coxa offsets
  set to 0: the owner re-horns those two servos (the old +-90 left them
  at the end of travel; the sim showed them clamping).
- ServoDriver: 18 servos on hardware PWM (50 Hz, 16-bit); the Teensy 3.6
  Servo library stops at 12.
- Radio on CE 39 / CSN 15 with SPI SCK on pin 14.
- sim: analogWrite/PWM shims, pulses decoded through SERVOS (API v6).
- Docs: CLAUDE.md, READMEs.

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

2026-current/Hexapod_Simulation_Unity/Assets/HexapodSim/HexapodSimNative.cs

@@ -38,7 +38,6 @@ namespace HexapodSim
         public float stanceRadiusMm, stanceHeightMm;
         public float coxaMinDeg, coxaMaxDeg, femurMinDeg, femurMaxDeg, tibiaMinDeg, tibiaMaxDeg;
         public float controlHz;
-        public int servoUsAt0Deg, servoUsPerDeg;
         public float legClearanceMm;
         public float stanceHeightRangeMm;
     }
@@ -72,7 +71,7 @@ namespace HexapodSim
     // "Reload firmware" and the new code runs. Each load is a fresh power-on.
     public sealed class HexapodSimNative : IDisposable
     {
-        public const int ExpectedApiVersion = 5;   // HXSIM_API_VERSION
+        public const int ExpectedApiVersion = 6;   // HXSIM_API_VERSION
 
         [UnmanagedFunctionPointer(CallingConvention.Cdecl)] delegate int IntFn();
         [UnmanagedFunctionPointer(CallingConvention.Cdecl)] delegate void VoidFn();