Battery indicator level tweaks

Verification

• I searched for similar issues (including closed issues) and found none was relevant.

Introduce the issue

I'm primarily using the PineTimeStyle, but I suspect it doesn't matter.

1. Charge battery to 99%, and the battery level indicator on the main clock display shows one pixel height already drained. In my mind, it's so close to 100%, that it should still appear as a full battery indicator.
2. At low battery, I can't remember if it is 10% or 15%, but swipe to the menu on the left, and you see the battery indicator in orange, so it is understood it is a low battery. But on the main clock display, it always shows the indicator as white, and is hard to see how low the indicator is for anything below about 20-25%.

Preferred solution

1. Round to the nearest, instead of rounding down. If there are 10 pixels height in the battery, it should be: 95-100%: full 10 pixels, 85-94%: 9 pixels, 75-84%: 8 pixels, ... 5-14%: 1 pixel, 0-4%: 0 pixels. Or similar - don't mind if it is 0-5%, 6-15%, etc.
2. I suggest putting the same orange battery indicator on the main clock display when the battery is below 15% (or 10% or whatever the threshold is). It currently turns red for 5% (?) and below, so I like that.

One consideration is that the watch face allows a custom colour for each component, and in fact, I do currently have PineTimeStyle with all orange colour highlights. So orange on orange would be invisible. The battery icon on the main watch fact currently has a black outline. Perhaps the battery icon could have a black outer border and a white inner outline, which changes to orange/red outline at low battery??

Version

1.15.0

Start by tracing the battery indicator used on the main clock display and the left-side menu, including their battery-level thresholds and color handling. Check whether watch-face custom colors and the existing red low-battery state are covered by tests. Done means the fill rounds as requested and low battery uses a visible orange or red treatment without breaking custom watch-face colors.