[FEATURE] Show remaining usage limits (5h/7 days) in VSCode extension and via CLI command

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

When working on long or complex tasks, I need to know how much of my usage limit (5-hour and 7-day rolling limits) remains before starting. Currently:

• In the interactive CLI, the limit appears visually in the footer during the session, but there is no command to query it outside of an active session.
• In the VSCode extension, only the context window usage is shown — the plan usage limits are not visible at all.
• There is no CLI flag, subcommand, or script to programmatically check remaining usage.

This forces me to open claude.ai in a browser just to check my remaining quota before deciding whether to start a large task.

Proposed Solution

1. Add a CLI command or flag to query remaining usage, e.g.: claude usage or claude --status
2. Show the remaining 5h/7-day limits in the VSCode extension status bar alongside the existing context window indicator
3. Optionally, expose this data via a simple API or local cache file so users can build their own scripts/integrations

Alternative Solutions

_No response_

Priority

Critical - Blocking my work

Feature Category

CLI commands and flags

Use Case Example

Before starting a large refactoring session or a multi-file feature implementation,
I want to quickly check how much of my usage limit remains — without leaving my
editor or opening a browser. A simple claude usage in the terminal or a visible
indicator in the VSCode status bar would let me decide whether to proceed now or
wait for the limit to reset.

Additional Context

_No response_