[BUG] VSCode: ide_selection and ide_opened_file missing on first message when using a skill

Bug

When invoking a skill (slash command) in the VSCode extension, ide_selection and ide_opened_file context tags are not included in the first message, even though the UI shows lines selected and a file is open.

Sending a follow-up message correctly includes both tags.

<img width="500" alt="Image" src="https://github.com/user-attachments/assets/1cc1322a-67b3-4beb-a804-7faf101159dd" />

What Should Happen?

ide_selection and ide_opened_file should be included in the skill's first message.

Steps to Reproduce

1. Create a custom skill in .claude/skills/my-skill.md
2. Open a file in the editor (e.g. src/index.ts)
3. Select some lines — UI shows </> N lines selected
4. Send: /my-skill do you have access to the selected lines?
5. Claude responds that it has no ide_selection or ide_opened_file in context
6. Send a follow-up: and now?
7. Claude now correctly sees both ide_selection and ide_opened_file

Environment

• VSCode extension
• Claude Code Version: 2.1.74
• Platform: Anthropic API
• Operating System: macOS

Preflight Checklist

• [x] I have searched existing issues 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