[FEATURE] Add context usage indicator so users can gauge how full the context window is

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

The /compact command previously cleared the conversation window, which allowed users to use the scroll indicator as a rough gauge of context fullness. Since that behavior changed (the window now keeps full history visible), there is no longer any way to tell how full the context window is or when auto-compact might fire (which is my main concern).

Proposed Solution

A visible indicator of current context usage — for example, a percentage, a progress bar, or a token count — shown somewhere in the UI (status bar, header, or as output from a command like /status). This would let users decide when to manually /compact before auto-compact fires unexpectedly.

Alternative Solutions

Relying on the scroll indicator in the conversation window is no longer viable, as the window now shows the full, uncompressed history regardless of the compact state.

Priority

High - Significant impact on productivity

Feature Category

Interactive mode (TUI)

Use Case Example

While working on a long coding session, I need to know when to run /compact before the context fills up and auto-compact fires unexpectedly. Previously, the scroll indicator in the conversation window served this purpose. Now that the window keeps full history visible after /compact, the scroll indicator no longer reflects actual context usage, leaving no way to gauge when I'm approaching the limit.

Additional Context

I'm using Claude Code v2.1.104 on Claude Pro on Windows Terminal. The change to keep conversation history visible after /compact was intentional and welcomed by other users — this request is not asking to revert that. It's only asking for a replacement signal, so users who relied on the scroll indicator have another way to gauge context fullness.