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.

examples/TH-141/固气界面/lemmas/固体表面能的晶面各向异性/element.toml

@@ -0,0 +1 @@
+kind = "lemma"

examples/TH-141/固气界面/lemmas/固体表面能的晶面各向异性/stmt.typ

@@ -0,0 +1,3 @@
+不同晶面的表面原子缺键数不同，故 $gamma_(S G)$ 随晶面指数 $(h k l)$ 而变。以简单立方为例：(100) 缺 1 键、(110) 缺 2 键、(111) 缺 3 键，从而
+
+$ gamma_(S G)^((100)) < gamma_(S G)^((110)) < gamma_(S G)^((111)) . $ <晶面各向异性>

examples/TH-141/固气界面/lemmas/拉伸固体的总应力/element.toml

@@ -0,0 +1 @@
+kind = "lemma"

examples/TH-141/固气界面/lemmas/拉伸固体的总应力/proof.typ

@@ -0,0 +1,9 @@
+设固体体积 $V$、表面积 $A$，应变 $epsilon$ 为均匀小量。体相单位体积的自由能 $f_b = Y epsilon^2 \/ 2$，表面单位面积的自由能 $gamma(epsilon)$，总自由能
+
+$ F = V f_b + A gamma(epsilon) . $
+
+对均匀拉伸 $V epsilon$ 求导得单位横截面承担的应力
+
+$ sigma_("tot") = (partial F) / (partial (V epsilon)) = Y epsilon + A / V dot (dif gamma) / (dif epsilon) , $
+
+即 @总应力。

examples/TH-141/固气界面/lemmas/拉伸固体的总应力/stmt.typ

@@ -0,0 +1,5 @@
+对横截面被均匀拉伸的固体，单位横截面承担的总应力为
+
+$ sigma_("tot") = Y epsilon + A / V dot (dif gamma) / (dif epsilon) , $ <总应力>
+
+其中 $Y$ 为杨氏模量、$epsilon$ 为应变、$A \/ V$ 为表面积与体积之比。第一项为体相弹性贡献，第二项为表面贡献。

examples/TH-141/固气界面/lemmas/缺键模型迁移到固气/element.toml

@@ -0,0 +1 @@
+kind = "lemma"

examples/TH-141/固气界面/lemmas/缺键模型迁移到固气/stmt.typ

@@ -0,0 +1,5 @@
+固气界面 $gamma_(S G)$ 的缺键模型公式由 @缺键一般式 直接迁移，只把摩尔汽化热 $L_m$ 替换为摩尔升华热 $L_s$：
+
+$ gamma_(S G) = (1 - zeta) thin L_s thin rho^(2\/3) / (mu^(2\/3) thin N_A^(1\/3)) . $ <固气缺键式>
+
+物理来源也只是把"把分子从液体里拉出来"换成"把原子从晶格里拉出来"，骨架公式 @骨架公式 与单键计数过程不变。