Add Support for Math Helpers in Handlebars Charts

What is the problem or goal the end user is trying to solve or accomplish?

Users need to perform simple arithmetic operations directly in Handlebars templates (e.g., converting milliseconds to seconds, dividing values, computing ratios, etc.) to format numeric data dynamically in visualizations.

How are they solving it currently?

They must handle all numeric transformations upstream in SQL, dbt models, or other ETL processes before the dataset reaches Preset. This limits flexibility and increases modeling overhead for simple presentation logic.

What is the recommended solution by the Customer?

Enable built-in math helpers (e.g., add, subtract, multiply, divide, mod, floor, ceil) in Preset’s Handlebars chart environment — similar to those provided by the just-handlebars-helpers library. This would allow users to perform lightweight calculations directly in templates without relying on external transformations.