This PR introduces custom syntax highlighting rules for GritQL in Zed, relying on the official tree-sitter parser from honeycombio.

There are two building blockers that make up syntax highlighting

• Tree-sitter parser: Implemented in https://github.com/honeycombio/tree-sitter-gritql
• Syntax highlighting rules: Documented at https://zed.dev/docs/extensions/languages#syntax-highlighting

While we could use the recently released https://zed.dev/extensions/grit extension, it has a few limitations:

1. Missing highlighting rules for regex, intConstant, signedIntConstant, arithmetic ops, multifile, etc
2. Its underlying Tree-sitter parser is branched off from the official one
3. Defines tab_size metadata which could conflict with biome formatter for GritQL.

Defining our own rules (as in this PR) allows us to ensure full coverage and compatibility, with minimal overhead. Relying on the official parser also makes future maintenance easier. Any custom syntax (e.g., ‎engine biome) can be contributed and converged with the official parser for broader support.

There are two TODO items I wish to accomplish after this PR:

• Highlight engine biome in addition to engine marzano (requires upstream fix to tree-sitter parser)
• Use Zed's code injection feature to properly highlight the code snippet inside GritQL.

See the screenshots below for a side-by-side comparison between our own rules and the GritQL extension.

Biome's rules

Existing GritQL extension's rules

Fixes: #125