Add RPM field to data model

[jorlandobr]

data_model.py now returns RPM value

I made that change to use a modified racebox template, adding the RPM field for a custom-made device that outputs data in the same fashion that racebox uses,

[LaurensVR3]

Good catch on the gap — rpm and exhaust_temp were already added as generic fields on DataPoint (they're populated for AIM and MoTeC already), just never wired up for the RaceBox loader. So this isn't adding a source-specific field, it's finishing something already started, and it's the right file to touch.

The logic itself works, but it calls row.get() three times and the leftover comments/dead line make it hard to follow. Suggested cleanup:

raw_rpm = row.get('Rpm', row.get('rpm'))
rpm = float(raw_rpm) if raw_rpm not in (None, '', 'None') else 0.0,

Same behavior (falls back to 0.0 on missing/empty/None), fewer dict lookups, and drops the commented-out dead line + duplicate 'FIX:' comments. Happy to take this once it's cleaned up.

[jorlandobr]

Using raw_rpm failed the tests. I tried this way, and it works:

           # FIX: Only convert to float if raw_rpm is not None/empty string, else default to 0.0
            rpm        = float(row.get('Rpm', row.get('rpm', 0.0)) or 0.0),

Dead lines removed.