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/sim/HexapodSimApi.cpp

@@ -50,8 +50,6 @@ HXSIM_API void hxsim_get_geometry(HxGeometry* g) {
   g->femur_min_deg = FEMUR_MIN_DEG; g->femur_max_deg = FEMUR_MAX_DEG;
   g->tibia_min_deg = TIBIA_MIN_DEG; g->tibia_max_deg = TIBIA_MAX_DEG;
   g->control_hz = CONTROL_HZ;
-  g->servo_us_at_0deg = SERVO_US_AT_0DEG;
-  g->servo_us_per_deg = SERVO_US_PER_DEG;
   g->leg_clearance_mm = LEG_CLEARANCE_MM;
   g->stance_height_range_mm = STANCE_HEIGHT_RANGE_MM;
 }
@@ -105,22 +103,24 @@ HXSIM_API int32_t hxsim_serial_output(char* out, int32_t cap) { return simhw::se
 HXSIM_API void hxsim_get_servos(int32_t* us, int32_t* attached, uint32_t* writes) {
   for (int i = 0; i < NUM_LEGS; i++)
     for (int j = 0; j < 3; j++) {
-      const simhw::ServoPin& p = simhw::servoPin(SERVO_PINS[i][j]);
+      const simhw::ServoPin& p = simhw::servoPin(SERVOS[i][j].pin);
       if (us)       us[i * 3 + j] = p.us;
       if (attached) attached[i * 3 + j] = p.attached ? 1 : 0;
       if (writes)   writes[i * 3 + j] = p.writes;
     }
 }
 
-// Inverse of ServoDriver::degToMicros - what angle the firmware meant.
-static float pulseToDeg(int us) {
-  return (us - SERVO_US_AT_0DEG) / (float)SERVO_US_PER_DEG;
+// Inverse of ServoDriver::degToMicros through the same per-servo table:
+// what angle the firmware meant by this pulse.
+static float pulseToDeg(int leg, int joint, int us) {
+  const ServoCal& c = SERVOS[leg][joint];
+  return (us - c.us_at_0deg) / c.us_per_deg;
 }
 
 HXSIM_API void hxsim_get_joints_deg(float* deg) {
   for (int i = 0; i < NUM_LEGS; i++)
     for (int j = 0; j < 3; j++)
-      deg[i * 3 + j] = pulseToDeg(simhw::servoPin(SERVO_PINS[i][j]).us);
+      deg[i * 3 + j] = pulseToDeg(i, j, simhw::servoPin(SERVOS[i][j].pin).us);
 }
 
 // Forward kinematics, written independently of robot/Kinematics.cpp so it