tool: enable custom icons

[bendrucker]

Adds a customizable icon prop to ToolHeader, allowing users to replace the default wrench icon with custom icons — either statically or dynamically based on tool name and state.

Changes

• Adds icon prop to ToolHeaderProps accepting a ReactNode or a render function (props: ToolIconProps) => ReactNode
• The render function receives { type, state, toolName, className } — providing full tool context and default sizing/color styles via className
• Extracts ToolPartProps as a shared base type for both ToolHeaderProps and ToolIconProps
• Exports ToolIconProps so consumers can type their icon render functions
• Falls back to the default WrenchIcon when icon is not provided or returns null
• Adds shrink-0 to the default icon className to prevent flex shrinking

Testing

Verified rendering in the docs dev server with custom SVG icons, name-based icon mapping, and fallback to default:

[vercel]

@bendrucker is attempting to deploy a commit to the Vercel Team on Vercel.

A member of the Team first needs to authorize it.