feat: integrate ANTLR parser - #9

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4, actions/setup-node@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

'_textDocumentPosition' is defined but never used

'document' is defined but never used

'document' is defined but never used

'name' is assigned a value but never used

'_event' is defined but never used

'hasDiagnosticRelatedInformationCapability' is assigned a value but never used

'_error' is defined but never used