IDE validator does not recognize 'allowed-tools' in skill frontmatter

Description

The VS Code extension (Claude Code IDE integration) reports a warning for the allowed-tools field in skill YAML frontmatter:

Attribute 'allowed-tools' is not supported in skill files. Supported: compatibility, description, license, metadata, name.

However, allowed-tools is a valid field documented in both:

• agentskills.io specification (listed as experimental)
• Claude Code documentation (code.claude.com) — with syntax examples like Bash(git:*)

The IDE validator's allowlist does not include allowed-tools, causing a false warning.

Steps to Reproduce

1. Create a skill file at .claude/skills/<name>/SKILL.md
2. Add allowed-tools: Bash(git:*) to the YAML frontmatter
3. Open the file in VS Code with the Claude Code extension installed
4. Observe the warning on the allowed-tools line

Expected Behavior

allowed-tools should be recognized as a valid frontmatter attribute without any warning.

Actual Behavior

Warning: Attribute 'allowed-tools' is not supported in skill files. Supported: compatibility, description, license, metadata, name.

Related Issues

• anthropics/skills#249 — skill-creator rejects valid optional fields
• #18837 — allowed-tools not correctly applied in some cases
• #18737 — allowed-tools support inconsistency between CLI and Agent SDK

Environment

• Claude Code VS Code Extension (latest)
• macOS