Function process_text 

pub fn process_text(input: &str) -> Line<'static>

Process text with emoji and markdown formatting.

Processing order:

1. Backticks (code) - processed first, content protected from further formatting
2. Emoji replacement - applied to text segments only
3. Bold (text) and italic (text) - applied to text segments only

Returns a Line containing styled Spans for Ratatui rendering.

Examples

let line = process_text("This is *bold* and :) `code`");
// Returns: Line with styled spans: "This is ", bold("bold"), " and 🙂 ", code("code")