Port piNail2 web UI and API parity to ESP32-C3 with one-side pin mapping

HARDWARE.md

@@ -9,16 +9,16 @@
 - Relay: SSR/mechanical relay, active HIGH.
 
 ## GPIO
-- `GPIO2`: relay output
-- `GPIO4`: MAX6675 SCK
-- `GPIO5`: MAX6675 CS
-- `GPIO6`: MAX6675 SO
+- `D10`: relay output
+- `D9`: MAX6675 SCK
+- `D8`: MAX6675 CS
+- `D7`: MAX6675 SO
 
 ## Safety defaults
 - Max temp cutoff: `800F`
 - Idle shutoff: `30 min`
 - Near setpoint band for idle: `+/-8F`
 
-## Fixed control timing
-- PWM/control loop window: `1800ms`
-- Control tick: `200ms`
+## Control timing
+- Adjustable via API/UI (`loop_size_ms` and `sleep_time`)
+- Default profile is responsive (`1800ms` loop window, `0.2s` tick)