ToolSearch 'Tool loaded.' result renders as user input in VS Code extension

Description

When using Claude Code in the VS Code extension, the ToolSearch tool returns a "Tool loaded." confirmation message that renders in the conversation as if it were user input rather than a system/tool response.

Steps to Reproduce

1. Open Claude Code in VS Code extension
2. Start a conversation that triggers a deferred tool load (e.g., any tool from the available-deferred-tools list)
3. Observe that "Tool loaded." appears styled as a user message bubble

Expected Behavior

The "Tool loaded." text should either:

• Not be displayed at all (it's an internal detail the user doesn't need to see)
• Be rendered as a system/tool response, not as user input

Actual Behavior

"Tool loaded." appears in the conversation formatted identically to user-typed messages, making it look like the user said "Tool loaded." — which is confusing and breaks the conversation flow.

Environment

• Claude Code VS Code extension
• Windows 11
• Started appearing recently (was not present a few days ago)