Function format_catchup_url 

pub fn format_catchup_url(
    template: &str,
    start: i64,
    duration_secs: i64,
    catchup_id: Option<&str>,
    timezone_shift_secs: i32,
) -> String

Format a catchup URL template by substituting all time-related placeholders.

This is the main entry point, translated from FormatDateTime() in CatchupController.cpp.

Arguments

• template - URL template with placeholders
• start - Programme start time (UTC epoch seconds)
• duration_secs - Programme duration in seconds
• catchup_id - Optional programme catchup ID for {catchup-id} substitution
• timezone_shift_secs - Timezone offset to apply (channel tvg-shift + correction)