Display API usage/rate limit status in VSCode UI

Feature Request

Add visibility into Claude API account usage and rate limits directly in the VSCode extension UI.

Problem

Currently there's no way to see how much of my 5-hour usage window remains without leaving the editor and checking the Claude dashboard. This makes it harder to plan work sessions and know when I might hit usage limits.

Requested Solution

Display session usage statistics next to the Bypass permission and Agent tool input line in the UI, showing:

• Remaining time in current 5-hour window
• Token usage (input/output) for the session
• Current rate limit status

Benefits

• Better work planning and session pacing
• Early warning before hitting rate limits
• Reduced context switching (no need to check dashboard)