feat(examples): migrate TH-141 sample to declarative layout (WU-6)

Real-content fixture for the end-to-end pipeline. TH-141 (39 parts: 22 segment,
15 lemma, 2 example) migrated from the prototype's typst `#let parts` manifest
to ADR-0008: declarative manifest.toml (project+info+ordered parts+targets) +
per-element element.toml (kind + scalars; examples carry `source`). Content .typ
files copied byte-identical (no math corruption); per-element main.typ + meta.toml
dropped (wiring is now generated). Part order matches source exactly; 5 lemmas
have no proof.typ (optional); no cross-file imports / paralearn refs / figs.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

examples/TH-141/lemmas/GGZ浸润判据/element.toml

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

examples/TH-141/lemmas/GGZ浸润判据/proof.typ

@@ -0,0 +1,13 @@
+把 @GG公式 给出的 $gamma_(S L) = (sqrt(gamma_(S G)) - sqrt(gamma_(L G)))^2$ 代入 @Young方程：
+
+$ cos theta = (gamma_(S G) - (sqrt(gamma_(S G)) - sqrt(gamma_(L G)))^2) / gamma_(L G) . $
+
+展开右端分子：
+
+$ gamma_(S G) - (gamma_(S G) - 2 sqrt(gamma_(S G) gamma_(L G)) + gamma_(L G)) = 2 sqrt(gamma_(S G) gamma_(L G)) - gamma_(L G) , $
+
+代回得
+
+$ cos theta = 2 sqrt(gamma_(S G) / gamma_(L G)) - 1 , $
+
+即 @GGZ判据。

examples/TH-141/lemmas/GGZ浸润判据/stmt.typ

@@ -0,0 +1,5 @@
+把 Berthelot 估计 @GG公式 代回 Young 方程 @Young方程，得到 Girifalco–Good–Zisman 浸润判据
+
+$ cos theta = 2 sqrt(gamma_(S G) / gamma_(L G)) - 1 . $ <GGZ判据>
+
+接触角完全由比值 $gamma_(S G) \/ gamma_(L G)$ 一个无量纲数决定。