Feature request: make activity heatmap thresholds configurable

Summary

The activity heatmap on the home screen uses fixed color thresholds (<1h, 1–3h, 3–5h, >5h), with the darkest shade applied to any day over 5 hours. I try to always have Foqos on (to essentially make my phone a dumb-phone), so every day exceeds 5h, so the entire heatmap is the same darkest color and doesn't convey anything meaningful

I'd like the thresholds (or an overall scale) to be configurable, so days where the profile was off, or off for longer, stand out from days it ran all day.

Current behavior

Every day looks identical because the scale tops out at 5h:

Where this lives in the code

The buckets are currently hardcoded:

https://github.com/awaseem/foqos/blob/1aac03d7ef1c9912cbe73a68af856e1ae60d2b21/Foqos/Components/Dashboard/FourWeekHeatmapView.swift#L13-L15

Possible approaches

• User-configurable thresholds: let users set the hour boundaries (and legend labels would update to match)
• Relative/adaptive scale: scale colors against the max (or a percentile) of the visible 4-week window, so variance always shows regardless of absolute hours.
• Preset modes: e.g. a "high usage" preset that shifts the bands upward for always-on profiles. You could default to have this on for pause profiles

I am a software engineer, so I'm happy to jump in and solve this with a PR, especially if you let me know if you like or don't like any of those directions. I am loving Foqos; I basically always have my phone bricked now!