Status line / usage stats: context usage, cache hits, token counters, usage limits

[dan64]

Feature Description

Standard status-line info request: the TUI footer should show, at minimum:

• Context usage (current % and/or tokens of context window)
• Cache hits (prompt cache reads/writes per session/request)
• Tokens received / sent (per request and cumulative)
• Usage statistics: monthly cost, total tokens, 5-hour usage limit, weekly limit

Also: cmd.ui.setStatus / cmd.ui.widget are documented but currently no-op in the TUI ("not wired yet") — wiring those would give users and mods a way to surface this data themselves.

Use Case

No response

Additional Context

No response

How important is this to you?

None

[dan64]

I closed because duplicated with #613