feat: add --reset and --trigger-error-state to hendi_ctrl_app.py

--trigger-error-state deliberately reproduces the Hendi's
ungraceful-disconnect lockout (remoteEnable(True) without a matching
disable) so it can be tested on demand. --reset toggles the reset
line, but per hardware testing it does NOT clear that lockout - only
the device's physical knob/power cycle does.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GpePKZiEZWbGo9HrfuML6U

scripts/hendi_ctrl_app.py

@@ -41,6 +41,24 @@ def test_heater(hendi):
 		hendi.setSwitch(0)
 
 
+def trigger_error_state(hendi):
+	"""Enables remote control and deliberately exits without disabling it
+	again - reproduces the Hendi's "not closed gracefully" lockout (its
+	built-in security feature that fails subsequent connect attempts)
+	on demand, instead of waiting for an actual crash to trigger it."""
+	print("Triggering error state: enabling remote control, exiting without releasing it")
+	hendi.remoteEnable(True)
+
+
+def reset(hendi):
+	"""Toggles the reset line. Confirmed on hardware that this does NOT
+	clear the ungraceful-disconnect lockout (see trigger_error_state()) -
+	only the device's physical knob/power cycle does that."""
+	print("Resetting Hendi (toggling DTR/RTS)")
+	hendi.reset()
+	time.sleep(1.0)
+
+
 def update_firmware(hendi, filename):
 	hendi.firmware_update(filename)
 
@@ -49,15 +67,20 @@ def main():
 	parser = ap.ArgumentParser(description=__doc__)
 	parser.add_argument("--serial-port", default=DEFAULT_PORT)
 	parser.add_argument("--baudrate", type=int, default=DEFAULT_BAUDRATE)
+	parser.add_argument("--reset", action="store_true", help="toggle the reset line (does not clear the ungraceful-disconnect lockout - use the device's knob for that)")
 	parser.add_argument("--version", action="store_true", help="print software identifier/version")
 	parser.add_argument("--capabilities", action="store_true", help="print power/digit capability info")
 	parser.add_argument("--test-converter", action="store_true", help="round-trip the watts<->digits polynomials")
 	parser.add_argument("--test-heater", action="store_true", help="drive the heater through its power range")
+	parser.add_argument("--trigger-error-state", action="store_true",
+		help="enable remote control and exit without disabling it, to deliberately reproduce the ungraceful-disconnect lockout")
 	parser.add_argument("--update-firmware", metavar="FILE", help="flash the given firmware file")
 	args = parser.parse_args()
 
 	hendi = HendiCtrl(args.serial_port, args.baudrate)
 
+	if args.reset:
+		reset(hendi)
 	if args.version:
 		print_version(hendi)
 	if args.capabilities:
@@ -66,6 +89,8 @@ def main():
 		test_converter(hendi)
 	if args.test_heater:
 		test_heater(hendi)
+	if args.trigger_error_state:
+		trigger_error_state(hendi)
 	if args.update_firmware:
 		update_firmware(hendi, args.update_firmware)