VSCode Extension: Show persistent token/context usage indicator

Feature Request

The CLI version of Claude Code displays token usage in the status line, but the VSCode extension has no persistent token counter.

Current behavior

Token count is not visible in the VSCode extension. Users only notice the context is getting full when they receive an error:
"API Error: Usage credits required for 1M context"

This is especially problematic since auto-compact used to trigger at ~168K tokens (with claude-sonnet-4-6 on ~200K context), but recent versions appear to attempt the 1M context window first — meaning the error occurs before auto-compact kicks in.

Expected behavior

A persistent indicator (e.g. in the chat header, input area, or VS Code status bar) showing current token usage, e.g. "168K / 200K tokens" or a progress bar.

Why this matters

Without visibility into context usage, users cannot proactively run /compact and are forced to restart the session when the error occurs.

Claude Code version: 2.1.168
Platform: Windows 11, VSCode extension