M4: read page transitions and display times (/Trans, /Dur) into DocInfo (#2074)

Each page's presentation settings of ISO 32000-2 s12.4.4 are read with the
spec's defaults for what is missing or out of range: the transition style,
duration, dimension, motion, direction, Fly scale and backdrop, and the
/Dur display time. doc_info lists them; pdfcraft-cli info counts them.
This is the data full screen needs to play transitions and auto-advance;
playing and editing them stay planned.

Refs #379, #2070.


Claude-Session: https://claude.ai/code/session_01RUNQSPVXx3dDBabRZHAnjz

Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>

apps/pdfcraft-cli/src/main.rs

@@ -312,6 +312,7 @@ fn info(args: &[String]) -> Result<(), CliError> {
         "xfa_layout": xfa_layout,
         "bookmarks": info.outline.len(), "annotations": info.annotations.len(), "fields": info.fields.len(),
         "links": info.links.len(), "layers": info.layers.len(), "attachments": info.attachments.len(),
+        "transitions": info.transitions.len(),
         "page_labels": info.pages.iter().take(8).map(|p| p.label.clone()).collect::<Vec<_>>(),
         "warnings": info.warnings,
     });