Show remaining 5-hour and weekly subscription limits as percentages in the top bar (100%/100%)

[jpacka]

Area
apps/web (and shared header/toolbar components), usage-limits data surface
Problem or use case
Subscription rate limits (especially the rolling 5-hour window and the weekly window) are critical when driving agents for extended periods. The existing Usage → Limits page and the /usage-limits composer command already expose accurate pooled remaining percentages for these windows. However, both require leaving the current thread or opening a separate view.
As a result, it is easy to exhaust a window without real-time visibility while staying on the main working screen. Other tools (menu-bar widgets, status-bar extensions, etc.) solve this by keeping a compact remaining-percentage indicator always visible. T3 Code currently lacks an equivalent glanceable indicator in the primary UI chrome.
Proposed solution
Display the remaining percentages for the two primary subscription windows directly in the top bar (the header that contains the current thread title, “+ Add action”, “Open”, “Initialize Git”, etc.).
Desired format and behaviour

Always show two percentages side-by-side in the form XX%/YY%.
First number = remaining percentage of the 5-hour limit.
Second number = remaining percentage of the weekly limit.

When no usage has been consumed (or limits are fully available), display 100%/100%.
Update the values live as the underlying usage-limits snapshot changes, without requiring navigation away from the current screen.
Prefer the pooled view already implemented for Usage → Limits (one number per window across accounts/environments for the active provider context).
Keep the presentation minimal and non-intrusive so it fits the existing top-bar density.

Example (from current UI mock-up intent)

100%/100% placed in the top bar, decreasing as the 5-hour and weekly windows are consumed.
Expected behaviour

The indicator is visible on the main thread screen at all times (web/desktop primary surface).
Values reflect the same data source used by Usage → Limits and /usage-limits.
No extra page or popover is required to see the current remaining percentages.
The display remains readable and updates without disrupting the rest of the header layout.

Additional context

The data pipeline for these percentages already exists (pooled subscription limits for Claude, Codex, Grok, etc.).
Related prior work: pooled Limits view, mobile pooled subscription usage widgets, and earlier requests for more glanceable remaining-quota indicators (e.g. composer-toolbar chips).
This request is specifically for a persistent, always-visible top-bar percentage pair rather than a deeper drill-down or composer-only control.

Alternatives considered

Relying solely on Usage → Limits or the /usage-limits command (requires context switch).
A composer-toolbar chip showing only the single most-constrained bucket (useful, but does not satisfy the request for both windows visible at a glance from the first screen).

[jpacka]