APC UPS Daemon add missing power consumption sensors

### The problem

Adding UPS power consumption to the energy panel would be awesome. The integration could easily provide it as it already provides max load and percentage of use. That would provide instant consumption. Then with a riemann integral we could get kw/h.

### What version of Home Assistant Core has the issue?

core-2026.9.1

### What was the last working version of Home Assistant Core?

_No response_

### What type of installation are you running?

Home Assistant OS

### Integration causing the issue

apccupsd

### Link to integration documentation on our website

https://www.home-assistant.io/integrations/apcupsd/

### Diagnostics information

_No response_

### Example YAML snippet

```yaml

```

### Anything in the logs that might be useful for us?

```txt

```

### Additional information

_No response_

Start with the apccupsd integration documentation and inspect how it currently exposes maximum load and percentage of use. Add the missing power-consumption sensors so the values can appear in the energy panel and support the requested consumption calculation.

Written by the indexing model from the issue text.