Function t_fmt 

pub fn t_fmt(app: &AppState, key: &str, args: &[&dyn Display]) -> String

What: Get a translation with format arguments.

Inputs:

• app: AppState containing translation maps
• key: Dot-notation key
• args: Format arguments (as Display trait objects)

Output:

• Formatted translated string

Details:

• Replaces placeholders in order: first {} gets first arg, etc.
• Supports multiple placeholders: “{} and {}” -> “arg1 and arg2”