Show ambient temperature and warp factor in the GUI's status bar

Adds a 'System' channel for static, global info that doesn't belong
to any one task - sent once at startup directly from brewpi.py's
__main__ (a client connecting later still gets it via the
dispatcher's global_state replay on subscribe, same mechanism
SudTask's startup Name/Description already relies on).

Moves warp_factor out of SudTask's startup message and into this new
channel, since it's not actually Sud-specific - it's now available
(and the status bar shows it) even without a Sud configured. The
forecast plot's progress-line scaling switches to the same general
Window.warp_factor field.

Displayed via a permanent status bar widget (not cleared by the
existing transient step/schedule showMessage() calls).

client/brewpi_gui.py

@@ -190,10 +190,11 @@ class Window(QtWidgets.QMainWindow, Ui_MainWindow):
 		self.sud_loaded = False
 		self.sud_state = None
 		self.sud_user_message = None
-		# Simulated-seconds-per-real-second, from SudTask's 'WarpFactor'
-		# message; defaults to 1.0 (no scaling) until that arrives, or for
-		# a server that doesn't send it at all.
-		self.sud_warp_factor = 1.0
+		# Global, not Sud-specific - from the 'System' channel's one-time
+		# startup message. warp_factor defaults to 1.0 (no scaling) until
+		# that arrives, or for a server that doesn't send it at all.
+		self.ambient_temp = None
+		self.warp_factor = 1.0
 		# time.monotonic() of the last IDLE/DONE -> running transition, used
 		# to position the forecast plot's progress line; None while not
 		# running. sud_paused_total accumulates time spent PAUSED so the
@@ -208,6 +209,7 @@ class Window(QtWidgets.QMainWindow, Ui_MainWindow):
 		self.msg_stirrer = self.msg_dispatch.msgio_get('Stirrer')
 		self.msg_tempctrl = self.msg_dispatch.msgio_get('TempCtrl')
 		self.msg_sud = self.msg_dispatch.msgio_get('Sud')
+		self.msg_system = self.msg_dispatch.msgio_get('System')
 
 		self.msg_pot.set_recv_handler(self.on_pot_changed)
 		self.msg_sensor.set_recv_handler(self.on_sensor_changed)
@@ -215,8 +217,15 @@ class Window(QtWidgets.QMainWindow, Ui_MainWindow):
 		self.msg_stirrer.set_recv_handler(self.on_stirrer_changed)
 		self.msg_tempctrl.set_recv_handler(self.on_tempctrl_changed)
 		self.msg_sud.set_recv_handler(self.on_sud_changed)
+		self.msg_system.set_recv_handler(self.on_system_changed)
 
 		self.setupUi(self)
+		# Permanent (right-aligned, not cleared by showMessage()/clearMessage())
+		# label for static environment info - distinct from the status bar's
+		# transient step/schedule messages.
+		self.status_label_env = QtWidgets.QLabel()
+		self.statusBar().addPermanentWidget(self.status_label_env)
+		self.update_status_env_label()
 		self.update_sud_actions()
 		self.btn_connect.clicked.connect(self.on_btn_connect_clicked)
 		self.actionStart.triggered.connect(self.on_action_sud_start)
@@ -294,7 +303,7 @@ class Window(QtWidgets.QMainWindow, Ui_MainWindow):
 			elapsed_real_s = now - self.sud_start_time - self.sud_paused_total
 			# The forecast's x-axis is simulated-schedule time; scale real
 			# elapsed time by the server's warp factor to match it.
-			elapsed_min = elapsed_real_s * self.sud_warp_factor / 60.0
+			elapsed_min = elapsed_real_s * self.warp_factor / 60.0
 			self.forecast_plot.set_progress(elapsed_min)
 		else:
 			self.forecast_plot.clear_progress()
@@ -321,11 +330,13 @@ class Window(QtWidgets.QMainWindow, Ui_MainWindow):
 			self.sud_loaded = False
 			self.sud_state = None
 			self.sud_user_message = None
-			self.sud_warp_factor = 1.0
+			self.ambient_temp = None
+			self.warp_factor = 1.0
 			self.sud_start_time = None
 			self.sud_paused_total = 0.0
 			self.sud_pause_started_at = None
 			self.update_sud_actions()
+			self.update_status_env_label()
 
 	def update_sud_actions(self):
 		running = self.sud_loaded and self.sud_state in SUD_RUNNING_STATES
@@ -336,6 +347,19 @@ class Window(QtWidgets.QMainWindow, Ui_MainWindow):
 		self.actionPause.setEnabled(running)
 		self.actionStop.setEnabled(running or paused)
 
+	def on_system_changed(self, msg):
+		print("on_system_changed {}".format(msg))
+		for key in msg:
+			if "AmbientTemp" in key:
+				self.ambient_temp = msg['AmbientTemp']
+			elif "WarpFactor" in key:
+				self.warp_factor = msg['WarpFactor']
+		self.update_status_env_label()
+
+	def update_status_env_label(self):
+		ambient = "{:.1f}°C".format(self.ambient_temp) if self.ambient_temp is not None else "-"
+		self.status_label_env.setText("Ambient: {}   Warp: {:.1f}x".format(ambient, self.warp_factor))
+
 	def on_slider_temp_soll_changed(self, value):
 		print("on_slider_temp_soll_changed {}".format(value))
 		self.msg_tempctrl.send({'Soll': {'Temp': value}})
@@ -491,8 +515,6 @@ class Window(QtWidgets.QMainWindow, Ui_MainWindow):
 					self.update_sud_forecast(msg['Json'])
 			elif "Name" in key:
 				self.statusBar().showMessage("Sud schedule updated: {}".format(msg['Name']), 5000)
-			elif "WarpFactor" in key:
-				self.sud_warp_factor = msg['WarpFactor']
 			elif "State" in key:
 				prev_state = self.sud_state
 				self.sud_state = msg['State']