Fix fragile substring dispatch in TcTask.recv()

Replace 'Soll' in key / 'Temp' in subkey substring loops with direct
dict key presence checks, matching the message structure used in send.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Tqxrk8uj4M3w3d3eXm3xK8

tasks/tempctrl.py

@@ -35,15 +35,13 @@ class TcTask(ATask):
 		asyncio.create_task(self.send({'Enabled': value}))
 
 	async def recv(self, msg):
-		for key in msg.keys():
-			if 'Soll' in key:
+		if 'Soll' in msg:
 			submsg = msg['Soll']
-				for subkey in submsg.keys():
-					if 'Temp' in subkey:
+			if 'Temp' in submsg:
 				self.tc.set_theta_soll(submsg['Temp'])
-					if 'Rate' in subkey:
+			if 'Rate' in submsg:
 				self.tc.set_heatrate_soll(submsg['Rate'])
-			if 'Enable' in key:
+		if 'Enable' in msg:
 			self.tc.set_enabled(bool(msg['Enable']))
 
 	async def send(self, data):