docs: heat pump protection limits and CWU history

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/roadmap.md

@@ -68,6 +68,9 @@ Sources: [research/frisko/](../research/frisko/README.md).
 - Live read 2026-10-23 21:52 (5 blocks, 36 registers, 2.5 s): state 4227 = 0 (pump stop),
   program 4226 = 1 (weekly), all outputs 0, targets 4201–4203 = 180/310/80 (X10: room 18.0,
   CO supply 31.0, CWU 8.0, i.e. economy period). `WyCHL` 4119 = -14308: meaning unknown.
+- Protection, read 2026-10-23: TmaxPc 4158 = 52 °C (outlet limit, compressor stops above),
+  TmaxCWU 4149 = 55, HistCWU 4148 = 5, PriorCWU 4146 = 1, heater delay t_zwlGrz 4147 = 20.
+  History: pump outlet never above ~52–56 °C; CWU above ~48 °C only in summer (solar).
 - CWU today (Influx, 14 days): the pump heats it daily at ~11:00 and ~17:30 up to ~44 °C
   (~15–20 °C/h, pump outlet ~47 °C). Slow morning rises with the pump off come from solar.
 - Phone app: direct Modbus TCP, LAN only, 200–300 ms between requests, 5 s timeout.