Function from_json 

pub fn from_json(
    json: &[u8],
    plan: &ExecutionPlan,
) -> Result<HashMap<String, LiteralValue>, LemmaError>

Convert JSON values to typed Lemma values using the ExecutionPlan for type information.

This function converts JSON values to Lemma types with the following rules:

Lemma Type	Valid JSON Types	Conversion
Text	any	Strings pass through; numbers/booleans/arrays/objects serialize to JSON string
Number	number, string	Numbers pass through; strings are parsed as decimals
Boolean	boolean, string	Booleans pass through; strings parsed as “true”/“false”/“yes”/“no”/“accept”/“reject”
Percent	number, string	Numbers become percent; strings parsed (with or without %)
Date	string	ISO format “2024-01-15” or “2024-01-15T14:30:00Z”
Regex	string	Pattern string, optionally wrapped in /slashes/
Unit types	string	Format: “100 kilogram”, “5 meter”, etc.

Special handling:

• null values are skipped (treated as if the fact was not provided)
• Unknown facts return an error
• Unparseable values return an error with a descriptive message