feat(cph): add outline export command

crates/cph-check/src/lib.rs

@@ -130,6 +130,39 @@ pub fn check(root: &Path, engine: &Engine) -> CheckReport {
     }
 }
 
+/// Load and validate the lesson, then project it into an outline.
+///
+/// Outline output is derived from the manifest and part metadata, not from the
+/// rendered lesson body. It therefore runs the same load → structural → schema
+/// gates as other non-typst builds, but intentionally does not compile any
+/// target. An invalid lesson is never written in any outline format.
+pub fn outline(root: &Path) -> (Option<cph_model::OutlineDocument>, CheckReport) {
+    let mut diags = Vec::new();
+    let (lesson, load_diags) = cph_model::load(root);
+    diags.extend(load_diags);
+
+    let Some(lesson) = lesson else {
+        return (
+            None,
+            CheckReport {
+                diagnostics: dedup(diags),
+                lesson_loaded: false,
+            },
+        );
+    };
+
+    run_structural_and_schema(&lesson, cph_schema::known_kinds(), &mut diags);
+    let report = CheckReport {
+        diagnostics: dedup(diags),
+        lesson_loaded: true,
+    };
+    if report.has_errors() {
+        (None, report)
+    } else {
+        (Some(lesson.outline_document()), report)
+    }
+}
+
 /// Build a PDF for `target`.
 ///
 /// Runs the check phases **(a)–(c)** (load → structural → schema). If those