[Bug] LSP validation ignores valid $schema key in hooks.json

**Bug Description**
Claude Code errors on the "$schema" key in hooks.json, which is valid:
⏺ yaml-lsp: hooks.json: unknown key "$schema" ignored

⏺ bash-lsp: hooks.json: unknown key "$schema" ignored

**Environment Info**
- Platform: darwin
- Terminal: ghostty
- Version: 2.1.271
- Feedback ID: e165041b-f61b-4855-a56c-3b2bafdcffc4

**Errors**
```json
[]
```

Start by reproducing the validation messages for the "$schema" key in hooks.json on the reported environment, then trace the LSP validation entry point that handles this file. Done means a valid "$schema" key no longer produces the reported unknown-key errors in either yaml-lsp or bash-lsp.

Written by the indexing model from the issue text.