Show the even-pace point on Usage → Limits bars

[badmike]

The problem

Usage → Limits tells you how much quota is left, but not whether that is a lot or a little for the time still to run. A weekly window at 40% left is comfortable on day six and alarming on day two, and the bar reads the same either way. Today you have to read the countdown, do the division in your head, and compare.

The pace arrow next to the big number already encodes this verdict, but only as ahead/on/under. It cannot show you by how much, and it says nothing per account in a pooled bar.

The idea

Put the comparison on the bar itself. Each account segment gets a tick above and below it at the point even spending would have reached, so the distance between the tick and the fill edge is the headroom. Drawn in the provider colour, and only when the window reports both a duration and a reset — without a timeframe there is nothing to compare against and nothing is drawn.

Real data from my own account, before and after:

Before

After

Claude's weekly window (40% left, 39% at even pace) sits right on the line. Fable's (65% left, same clock) has an obvious margin. Same kind of number, different stories, and the tick makes it a glance instead of a calculation.

The narrow numbered strip gets the same treatment, scaled to the shorter bar:

Scope

Small. Two helpers in packages/shared/src/usageLimits.ts so web and mobile agree on the maths, the ticks on the pooled segments, and the exact figures in the segment popover. The two views that already drew this marker inline now call the shared helpers instead of repeating the arithmetic. No new dependencies, no contract changes, no docs.

Status

I have this working and pushed as #11063. I filed the PR before reading CONTRIBUTING properly — this discussion is the step I should have taken first, so treat the PR as a reference implementation rather than a request to merge. Happy to close it if the idea is not wanted, or to reshape it if the direction is right but the treatment is wrong.

One open question I would want your call on: whether the tick belongs only on the pooled bars, or also on the per-window bars in the composer's /usage-limits panel. Those already draw a hairline across the bar; I left them alone to keep the change small, but that means two visual languages for the same concept.