[BUG] Annotate tool: white crosshair cursor is invisible on light pages in the Browser pane

### Preflight Checklist

- [x] I have searched [existing issues](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20state%3Aopen%20label%3Abug) and this hasn't been reported yet
- [x] This is a single bug report (please file separate reports for different bugs)
- [x] I am using the latest version of Claude Code

### What's Wrong?

**Environment**
- Claude Code desktop app for Windows (Windows 11 Pro)
- Browser pane with the "Anotar" (Annotate) pencil tool

**Issue**
When I select the pencil (Annotate) tool in the Browser pane, the mouse cursor changes to a crosshair ("+") that is rendered in white with no outline. On light-themed pages (white or light-gray backgrounds) the crosshair becomes practically invisible, so I cannot see where the cursor is or what I am about to circle/mark.

**Steps to reproduce**
1. Open any light-background web app in the Browser pane (e.g. a white dashboard).
2. Click the pencil icon ("Anotar") to start annotating.
3. Move the mouse over the page.

**Expected**
The annotation cursor should be visible on any background — e.g. a crosshair with a dark outline/contrast border, or one that inverts against the page color.

**Actual**
White crosshair with no contrast; invisible over light content.

**Suggestion**
Use a two-tone crosshair (white with a black outline, or the reverse), or follow the OS pointer color/size settings.

### What Should Happen?

**Environment**
- Claude Code desktop app for Windows (Windows 11 Pro)
- Browser pane with the "Anotar" (Annotate) pencil tool

**Issue**
When I select the pencil (Annotate) tool in the Browser pane, the mouse cursor changes to a crosshair ("+") that is rendered in white with no outline. On light-themed pages (white or light-gray backgrounds) the crosshair becomes practically invisible, so I cannot see where the cursor is or what I am about to circle/mark.

**Steps to reproduce**
1. Open any light-background web app in the Browser pane (e.g. a white dashboard).
2. Click the pencil icon ("Anotar") to start annotating.
3. Move the mouse over the page.

**Expected**
The annotation cursor should be visible on any background — e.g. a crosshair with a dark outline/contrast border, or one that inverts against the page color.

**Actual**
White crosshair with no contrast; invisible over light content.

**Suggestion**
Use a two-tone crosshair (white with a black outline, or the reverse), or follow the OS pointer color/size settings.

### Error Messages/Logs

```shell

```

### Steps to Reproduce

**Environment**
- Claude Code desktop app for Windows (Windows 11 Pro)
- Browser pane with the "Anotar" (Annotate) pencil tool

**Issue**
When I select the pencil (Annotate) tool in the Browser pane, the mouse cursor changes to a crosshair ("+") that is rendered in white with no outline. On light-themed pages (white or light-gray backgrounds) the crosshair becomes practically invisible, so I cannot see where the cursor is or what I am about to circle/mark.

**Steps to reproduce**
1. Open any light-background web app in the Browser pane (e.g. a white dashboard).
2. Click the pencil icon ("Anotar") to start annotating.
3. Move the mouse over the page.

**Expected**
The annotation cursor should be visible on any background — e.g. a crosshair with a dark outline/contrast border, or one that inverts against the page color.

**Actual**
White crosshair with no contrast; invisible over light content.

**Suggestion**
Use a two-tone crosshair (white with a black outline, or the reverse), or follow the OS pointer color/size settings.

### Claude Model

None

### Is this a regression?

Yes, this worked in a previous version

### Last Working Version

_No response_

### Claude Code Version

2.1.220 (Claude Code)

### Platform

Anthropic API

### Operating System

Windows

### Terminal/Shell

Windows Terminal

### Additional Information

_No response_

Start at the Browser pane's Annotate pencil tool and reproduce the cursor on a light page in the Windows desktop app. Locate where the annotation crosshair cursor is selected, then verify it remains visible over both light and dark content and that annotation still works.

索引モデルが issue の本文から書いたものです。