Show usage headroom for the active model outside the usage limits panel

[ntnkrnr]

Problem

The usage limits panel shows remaining quota for each provider and window (Session, Weekly, Weekly · Fable). It also shows a pace indicator, like "Under pace: headroom left for the rest of the window." I check it many times a day to decide whether I can start a long agent run or should switch models. Each check means opening the menu, finding the right provider, and reading several cards.

Proposal

Show a compact usage indicator somewhere always visible, for example next to the model picker in the composer or in the thread header. It would cover only the provider and model the current thread uses.

• Show the tightest window for that model, e.g. Session 84% · 2h 21m, with the existing pace icon (under pace, on pace, over pace).
• Hover shows every window for that model: Session, Weekly, and any model-specific weekly limit such as Fable.
• Click opens the full usage limits panel.
• Tint it when a window is over pace or below a threshold, so it only draws attention when it matters.

Why

The panel already computes the "headroom left" signal. Right now it's hidden behind a menu, and it only helps if I see it before I send a message. Showing it next to where I pick the model lets me make that call without leaving the thread.

Optional

A setting to hide the indicator, or to choose between the tightest window only and all windows.