refactor: move pot hardware params and pid_type out of per-brew docs

Pot hardware constants (mass, material, L, Td) moved from sude/*.json
to config.json's Pot section; Sud/SudForecastEstimator accept pot_config
as baseline, per-brew pot sections may still override. Controller key
removed; pid_type moved into TempCtrl.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

config-real.json.tpl

@@ -1,9 +1,7 @@
 {
 	"ambient_temperature": 20,
-	"Controller" : {
-	"pid_type": "Smith"
-	},
  	"TempCtrl": {
+		"pid_type": "Smith",
 		"beta": 0.05,
 		"Hold": {
 			"kp": 0.4,
@@ -45,5 +43,11 @@
 	"TempSensor": {
 	    "type": "max31865",
 		"temp_offset": -0.15
+	},
+	"Pot": {
+		"mass": 5.96,
+		"material": "Edelstahl 18/10",
+		"L": 0.2,
+		"Td": 17
 	}
 }