[Desktop/macOS] Usage popover (next to model/effort) shows account limits but not current session token/context usage

Environment

• Claude desktop app (Code tab) 2.37337.1
• macOS 15.7.2 (Apple Silicon, arm64)

Problem

The Usage control is the ring icon at the bottom right of the composer, next to the model and effort selectors. Its popover shows only account-level numbers:

• Session limit (% used, reset time)
• Weekly limit (% used, reset time)
• Cloud session credits

It shows nothing about the current conversation: no tokens used, no share of the context window filled, no sign of how close auto-compaction is. The only per-session number in the UI is the small "Xs · N tokens" line under a reply, and that counts a single turn, not the session.

Expected

Add a current-session section to the Usage popover, or show it on the ring itself:

• Context used / context window (tokens and %)
• How close the session is to auto-compaction
• Ideally a breakdown on hover (input / output / cache)

Why it matters

• Without it you can't tell when auto-compaction is about to happen, and compacting currently loses visible history (see #102361).
• You can't manage context or cost: when to start a fresh session, when to /compact, when to hand off.
• The CLI shows this through its status line, so the desktop app has less information than the CLI.

Steps to reproduce

1. Open any session in the Code tab.
2. Click the ring icon at the bottom right, next to model/effort.
3. The popover shows only plan limits and credits. The current session's token/context usage isn't shown anywhere.