VS Code extension skill validator rejects valid frontmatter fields

Description

The VS Code extension's skill file (SKILL.md) frontmatter validator rejects several valid attributes that are documented and functional in the CLI.

Reproduction

1. Create a skill with allowed-tools in frontmatter:

``yaml
---
name: commit
description: Commit changes and push to GitHub
disable-model-invocation: true
allowed-tools: Bash(git *)
---
``

1. Open the file in VS Code with the Claude Code extension (v2.1.66)
2. Warning appears: Attribute 'allowed-tools' is not supported in skill files. Supported: argument-hint, compatibility, description, disable-model-invocation, license, metadata, name, user-invokable.

Expected

No warning — allowed-tools is a documented frontmatter field per https://code.claude.com/docs/en/skills#frontmatter-reference.

Actual validator vs. docs

| Field | Official docs | Extension validator |
|-------|:---:|:---:|
| name | ✅ | ✅ |
| description | ✅ | ✅ |
| argument-hint | ✅ | ✅ |
| disable-model-invocation | ✅ | ✅ |
| user-invocable | ✅ | ❌ (listed as user-invokable — typo) |
| allowed-tools | ✅ | ❌ missing |
| model | ✅ | ❌ missing |
| context | ✅ | ❌ missing |
| agent | ✅ | ❌ missing |
| hooks | ✅ | ❌ missing |
| compatibility | ❌ not in docs | ✅ listed |
| license | ❌ not in docs | ✅ listed |
| metadata | ❌ not in docs | ✅ listed |

The validator is missing 5 valid fields, includes 3 undocumented fields, and has a typo (user-invokable → user-invocable).

Environment

• VS Code extension: anthropic.claude-code v2.1.66
• OS: Windows 11 Pro