/// A parsed subtitle document containing a flat list of cues.
/// A single subtitle cue with a sequential ID and decoded text.
///
/// IDs are assigned sequentially starting from 1 during ASS parsing.
/// The `text` field contains decoded text (literal `\n` for newlines,
/// no ASS `\N` escapes). Override tags like `{\pos(...)}` are stripped
/// during translation and re-injected afterward.