Statusline should refresh after /compact

Description

The custom statusline command does not refresh after running /compact. The statusline only updates on the next API round-trip (when the user sends a message and Claude responds).

Steps to Reproduce

1. Configure a custom statusline command in ~/.claude/settings.json
2. Run a conversation until context usage is high (e.g., 82%)
3. Run /compact
4. Observe the statusline still shows the pre-compaction context usage (82%)
5. Send any message (e.g., "hello")
6. After Claude responds, the statusline now shows the post-compaction value (e.g., 25%)

Expected Behavior

The statusline should refresh immediately after /compact completes, reflecting the updated context_window.used_percentage and current_usage values without requiring an additional message round-trip.

Why It Matters

The context usage bar is the primary reason users run /compact — they want to see the freed context space immediately. Having to send a throwaway message to see the updated value is a confusing UX gap.

Environment

• Claude Code CLI
• Custom statusline via statusLine.type: "command"