Reworked handling of GLT / Rk1..Rk4 Operating Modes / Pumps and Valves

• Hardened controller probing against partial Modbus read failures and excluded the invalid CL59/UP3 gap on 2-circuit controllers.
• Reworked operating-mode handling with effective active_mode state, direct mode writes, separate AUTARK release and settling-aware verification.
• Added detailed operating-mode transition logging for field testing and diagnostics.
• Added Night mode support for Rk4 / DHW and corrected adjustable DHW temperature limits to 5–90 °C.
• Added per-circuit and controller-wide GLT operating-mode ownership states.
• Added explicit pump control modes (Auto / On / Off) using pump output and ownership coils without invalid GLT pre-writes.
• Added regression tests for delayed mode changes, normalized command readback, Rk4 Night and pump-control ownership/write behavior.