Cell: publish — add veil paragraph, mark sketch shipped

Sketch entry flipped to published: true so it appears in the homepage
listing and serves at /sketches/cell/ in PROD instead of redirecting
to /404. Prose gains a fourth note describing the moss-veil layer:
the noise-clustered base, 30-second linear fade, polygon-based
rebirth on canvas re-entry, and the cursor's quadratic momentum →
opacity coupling.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: RuitingMa

src/lib/sketches.ts

@@ -25,7 +25,7 @@ export type Sketch = {
 };
 
 export const SKETCHES: Sketch[] = [
-  { slug: 'cell',        href: '/sketches/cell/',        title: 'Cell',       date: '2026-05-06', kind: 'GENERATIVE',         summary: '格中钟摆。',     tint: 'moss' },
+  { slug: 'cell',        href: '/sketches/cell/',        title: 'Cell',       date: '2026-05-06', kind: 'GENERATIVE',         summary: '格中钟摆。',     tint: 'moss', published: true },
   { slug: 'shi',         href: '/sketches/shi/',         title: '识',          date: '2026-04-22', kind: 'AI · INTERACTIVE',   summary: '机器识字。',     tint: 'moss' },
   { slug: 'clinamen',    href: '/sketches/clinamen/',    title: 'Clinamen',   date: '2026-04-20', kind: 'AUDIO · GENERATIVE', summary: '河灯散布于水面。', tint: 'rust', published: true },
   { slug: 'smoke',       href: '/sketches/smoke/',       title: 'Smoke',      date: '2026-04-19', kind: 'GENERATIVE',         summary: '烟。',           tint: 'plum', published: true },

src/pages/sketches/cell.astro

@@ -18,4 +18,7 @@ if (import.meta.env.PROD && isDraft('cell')) return Astro.redirect('/404');
   <p class="note enter" style="--i: 5;">
     相机在格子里缓慢漂移，速度恒定，方向由极低频的一维噪声驱动，整张网格在数学上是无穷的——只有视野内的格子被赋予生命，离开视野就被遗忘，再次进入也只会从同样的哈希里复活。
   </p>
+  <p class="note enter" style="--i: 6;">
+    每片格子上蒙一层稀薄的青苔色，浓淡由二维平滑噪声给出——相邻几格常深浅相近，整图分作一片片云絮的浓淡区，间或几个极透明的孔。这层色在多边形从边界探入画面时最浓，30 秒内线性淡至全无；多边形整段离开再回视为新生。光标惊动的格子色随动量加浓，呈平方关系。
+  </p>
 </SketchLayout>