feat(cph): implement nested outline manifest and batch/combined export

ADR-0029 — nested outline manifest, supersedes ADR-0008's flat [[parts]]:
- cph-model: recursive loader over manifest.toml containers / element.toml
  leaves; Lesson.parts (pure elements, DFS order) + Lesson.outline (elements
  interleaved with section headings at their DFS-open position); rejects
  ambiguous/incomplete folders and root-vs-container table misplacement
- cph-diag: new DiagCode::ManifestMalformed for carrier-document structure
  errors (discharges an existing TODO)
- cph-typst: augmented manifest now serializes the outline (element/section
  entries) instead of a flat parts array
- render/lib.typ: render-lesson renders section headings at their depth
- examples/TH-141 migrated to 5 nested section containers + 3 root segments,
  byte-identical element order; smoke-verified via cph check/build + pdftotext

ADR-0030 — batch & combined export, extends ADR-0009/0011:
- cph build with no --target batches every declared target (repeatable
  --target for an explicit subset); any target failure => non-zero exit,
  per-target ledger, independent per-target execution
- cph-model: bundle.toml loader (directory + [info]/[targets.*]/ordered
  lessons with per-lesson target overrides)
- cph-typst: augmented bundle manifest (path-prefixed member outlines),
  Engine::{compile_check_bundle,build_bundle_pdf}
- render/lib.typ: render-bundle assembles member lessons under per-lesson
  headings, depth-shifts their own section headings, resets example/lemma
  counters at each lesson boundary by default
- cph-cli: `cph bundle <path> --target <name>` subcommand, same batching
  contract as `cph build`
- new bundle fixtures/tests (cph-model unit + cph-typst through-template PDF
  compile), smoke-verified via a real 2-lesson merged PDF

Verification: cargo fmt/clippy/test clean across the workspace (68 tests);
real cph check/build/bundle runs against TH-141 and a bundle fixture, PDF
content inspected via pdftotext.

crates/cph-typst/src/lib.rs

@@ -42,12 +42,12 @@ mod world;
 use std::path::PathBuf;
 
 use cph_diag::{DiagCode, Diagnostic};
-use cph_model::{Artifact, Lesson, Step, TargetConfig};
+use cph_model::{Artifact, Bundle, Lesson, Step, TargetConfig};
 use typst_kit::fonts::{self, FontStore};
 use typst_layout::PagedDocument;
 use typst_pdf::PdfOptions;
 
-pub use manifest::build_augmented_manifest;
+pub use manifest::{build_augmented_bundle_manifest, build_augmented_manifest};
 pub use world::{render_package_spec, LessonWorld, MANIFEST_VPATH};
 
 /// The compile/PDF engine: holds the shared font store and the on-disk location
@@ -142,7 +142,7 @@ impl Engine {
     /// Build the [`LessonWorld`] for `(lesson, target)`, or `Err(blocking)` when
     /// the request cannot be honored (see [`target_precheck`]).
     fn world_for(&self, lesson: &Lesson, target: &str) -> Result<LessonWorld, Vec<Diagnostic>> {
-        let template = target_precheck(lesson, target)?;
+        let template = target_precheck(target, &lesson.targets)?;
         let manifest_src = build_augmented_manifest(lesson);
         Ok(LessonWorld::new(
             lesson.root.clone(),
@@ -152,6 +152,60 @@ impl Engine {
             self.fonts.clone(),
         ))
     }
+
+    /// Compile-check `bundle` for `target` (ADR-0030) — same contract as
+    /// [`Engine::compile_check`], but over a [`Bundle`]'s own declared targets
+    /// and the augmented **bundle** manifest (each member lesson's outline,
+    /// path-prefixed to resolve against the bundle root).
+    pub fn compile_check_bundle(&self, bundle: &Bundle, target: &str) -> Vec<Diagnostic> {
+        let world = match self.world_for_bundle(bundle, target) {
+            Ok(world) => world,
+            Err(blocking) => return blocking,
+        };
+        let warned = typst::compile::<PagedDocument>(&world);
+
+        let mut out = Vec::new();
+        if let Err(errors) = &warned.output {
+            out.extend(map_all(&world, errors));
+        }
+        out.extend(map_all(&world, &warned.warnings));
+        out
+    }
+
+    /// Build a PDF for `bundle` / `target` (ADR-0030) — same contract as
+    /// [`Engine::build_pdf`], over a [`Bundle`]'s own declared targets.
+    pub fn build_bundle_pdf(
+        &self,
+        bundle: &Bundle,
+        target: &str,
+    ) -> Result<Vec<u8>, Vec<Diagnostic>> {
+        let world = self.world_for_bundle(bundle, target)?;
+        let warned = typst::compile::<PagedDocument>(&world);
+        let doc = match warned.output {
+            Ok(doc) => doc,
+            Err(errors) => return Err(map_all(&world, &errors)),
+        };
+        typst_pdf::pdf(&doc, &PdfOptions::default()).map_err(|errors| map_all(&world, &errors))
+    }
+
+    /// Build the [`LessonWorld`] for `(bundle, target)`: same shape as
+    /// [`Engine::world_for`], main file resolved under the **bundle** root and
+    /// the injected manifest built by [`build_augmented_bundle_manifest`].
+    fn world_for_bundle(
+        &self,
+        bundle: &Bundle,
+        target: &str,
+    ) -> Result<LessonWorld, Vec<Diagnostic>> {
+        let template = target_precheck(target, &bundle.targets)?;
+        let manifest_src = build_augmented_bundle_manifest(bundle);
+        Ok(LessonWorld::new(
+            bundle.root.clone(),
+            self.render_dir.clone(),
+            &template,
+            manifest_src,
+            self.fonts.clone(),
+        ))
+    }
 }
 
 impl Default for Engine {
@@ -160,13 +214,16 @@ impl Default for Engine {
     }
 }
 
-/// Validate a `(lesson, target)` request and resolve the template path to
-/// compile. Returns `Ok(template_path)` (relative to the lesson root) when the
-/// request is buildable, or `Err(blocking_diagnostics)` when it is not:
+/// Validate a `(targets, target)` request and resolve the template path to
+/// compile. Shared by [`Engine::world_for`] (a lesson's `targets`) and
+/// [`Engine::world_for_bundle`] (a bundle's own `targets` — ADR-0030 gives a
+/// bundle target the exact same build/artifact/step shape). Returns
+/// `Ok(template_path)` (relative to the lesson/bundle root) when the request is
+/// buildable, or `Err(blocking_diagnostics)` when it is not:
 ///
-/// - **Unknown target** (the `--target` name isn't in `lesson.targets`, and the
-///   lesson declares at least one target): a `SchemaViolation` error — a target
-///   must be declared in the manifest to be built (ADR-0009).
+/// - **Unknown target** (the `--target` name isn't in `targets`, and `targets`
+///   is non-empty): a `SchemaViolation` error — a target must be declared in
+///   the manifest to be built (ADR-0009).
 /// - **No declared targets at all**: not an error — callers (e.g. `cph-check`)
 ///   may compile-check a defaulted `"student"` target the lesson never declared.
 ///   The stock template path `exports/<target>.typ` is used (the framework
@@ -177,10 +234,10 @@ impl Default for Engine {
 ///   [`Step::Shell`], returns a clear "not yet implemented" `SchemaViolation`
 ///   rather than wrong output. The template is taken from the **first**
 ///   `TypstCompile` step (MVP: one step per target).
-fn target_precheck(lesson: &Lesson, target: &str) -> Result<PathBuf, Vec<Diagnostic>> {
-    let Some(tc) = lesson.targets.iter().find(|t| t.name == target) else {
-        if lesson.targets.is_empty() {
-            // Lesson declares no targets; the orchestrator compiles a defaulted
+fn target_precheck(target: &str, targets: &[TargetConfig]) -> Result<PathBuf, Vec<Diagnostic>> {
+    let Some(tc) = targets.iter().find(|t| t.name == target) else {
+        if targets.is_empty() {
+            // Declares no targets; the orchestrator compiles a defaulted
             // target. Use the stock template path (matches cph-model's default).
             return Ok(PathBuf::from(format!("exports/{target}.typ")));
         }