Statusline context percentage is inaccurate — shows 69% when context limit is already reached

Bug

The statusline shows ~69% context usage while the conversation has already hit "Context limit reached".

<img width="568" height="225" alt="Image" src="https://github.com/user-attachments/assets/77bd468f-8bbd-44d4-9bdb-c0ea75ccf80e" />

Steps to reproduce

1. Start a conversation with multiple MCP servers configured (10+ servers: Slite, Google Workspace, Airtable, Lemlist, Linkup, etc.)
2. Perform several tool calls that return large payloads
3. Observe the statusline percentage vs actual context availability

Expected behavior

The percentage should accurately reflect real context usage and reach ~95-100% before "Context limit reached" triggers.

Actual behavior

"Context limit reached" appears while the statusline still shows ~69%.

Environment

• Claude Code CLI
• Model: Opus 4.6
• Multiple MCP servers active (10+ servers with many deferred tools)
• macOS Darwin 25.3.0