Add Configuration of DHW Temperature (CDT) use case

[volschin]

Summary

Adds the Configuration Appliance client for Configuration of DHW Temperature (CDT) and supersedes the older draft #132 with the current use-case APIs and event lifecycle.

This contribution is stacked on #239 because CDT uses its shared HVAC API types and the Setpoint/HVAC client helpers. The CDT-specific change is commit 50de294.

Behavior and safety

• resolves setpoints only through the DHW system-function relations
• accepts any advertised operation mode, including auto when it maps unambiguously to exactly one DHW setpoint
• checks the remote SetpointListData write operation and the optional changeability flag
• validates complete min/max/step constraints before writing
• preserves unrelated entries by sending a full cached setpoint-list copy
• exposes the message counter and the remote result callback
• refreshes setpoint data after a successful device result
• fails closed for ambiguous DHW functions, relations, incomplete constraints, and duplicate target entries

The full-list write and omitted-changeability behavior reflect the interoperability behavior observed with a Vaillant VR940 gateway and retain the validation semantics already exercised in the eebus-bridge integration.

Verification

• go vet ./...
• go test -race ./...

[volschin]

Ping @andig

[andig]

Yes?

[volschin]

The missing part to complete DHW.

[andig]

Ah. Nothing evcc uses ;). I'd go for cdsf.StartOneTimeDhw.

[volschin]

The Start.OneTimeDhw only heats the water to the configured standard temp. This gives the Option to higher the temp for this action and set it back afterwards.