[BUG] "Tool loaded." confirmation rendered as user message in chat UI

Description

When deferred tools are loaded via ToolSearch, the confirmation message "Tool loaded." is rendered as a user turn (with the > input prompt) in the chat UI, as if the user typed it. This happens every time a deferred tool is discovered.

Steps to Reproduce

1. Start a Claude Code session (v2.1.70)
2. Trigger any action that requires a deferred tool (e.g., Bash, Read, Edit, WebSearch)
3. Observe "Tool loaded." appearing as a user message in the conversation

Expected Behavior

The "Tool loaded." confirmation should either be hidden entirely or rendered as a system message, not as a user turn.

Actual Behavior

"Tool loaded." appears with the > user prompt prefix, breaking the visual flow of the conversation. In a typical session this can happen 5-10 times.

Screenshot

<img width="1136" height="961" alt="Image" src="https://github.com/user-attachments/assets/71b0b96a-4ae7-41d9-ac08-5c86ee75377a" />

<!-- Note: Screenshot available but could not be attached via CLI. Shows multiple "Tool loaded." lines rendered as user input between actual user messages and Claude responses. -->

Environment

• Claude Code version: 2.1.70
• Platform: macOS (Darwin 24.6.0)
• Terminal: Claude Code CLI

Notes

Possibly related to the 2.1.70 fix for "empty responses immediately after ToolSearch" — the empty response was fixed but the confirmation may now be surfacing as a user turn instead.