v0.14: 截图美化素材迁移 + 散落改动归集

主线：从 PPT skill port 9 张截图舞台底 WebP，补齐 v0.11 当时只迁规则未迁素材的缺口。

新增
- assets/screenshot-backgrounds/style-a/ · 5 张 Editorial 底
  dune / forest-ink / indigo-porcelain / kraft-paper / monocle-classic
- assets/screenshot-backgrounds/style-b/ · 4 张 Swiss 底
  ikb-dot-gradient / lemon-green-dot-shadow / lemon-grid / safety-orange-halftone

模板
- template-editorial-card.html: 加 5 条 .frame-shot.bg-asset-* 规则
- template-swiss-card.html: 加 4 条 .frame-shot.bg-asset-* 规则
  两侧都带 fallback 实色，素材未加载时背景不透

文档
- screenshot-treatment.md: 新增 Solid vs Asset 小节 + 两张对照表 + 4 条 rules of thumb
  + 两条新 cheat-sheet recipe，明确路径假设与 accent 绑定
- HANDOFF.md: 版本号 v0.14，目录树加 screenshot-backgrounds/，
  写清"素材迁移不是规则迁移"的边界（未引入 PPT 原 7 参数语义系统）

顺带归集本轮工作期间累积的散落改动（PRODUCT/SKILL/category-cookbook/
components/content-planning/map-component/production-workflow/
qa-checklist/style-system/validate-social-deck）一并入库，避免长期挂在 dirty tree。

assets/template-editorial-card.html

@@ -141,6 +141,7 @@
     .poster.xhs    { width: 1080px; height: 1440px; }
     .poster.square { width: 1080px; height: 1080px; }
     .poster.wide   { width: 2100px; height:  900px; }
+    .poster figure { margin: 0; }
 
     /* Default content padding by board */
     .poster.xhs    .content { padding: 96px 88px; }
@@ -419,6 +420,14 @@
       background-size: 18px 18px;
     }
 
+    /* asset backgrounds — ported from PPT skill, real texture for screenshot wells */
+    /* path is relative to the deck's index.html — keep seed and final deck in same dir, or override */
+    .frame-shot.bg-asset-dune             { background: #d8c9a8 url("../assets/screenshot-backgrounds/style-a/dune.webp")             center/cover no-repeat; }
+    .frame-shot.bg-asset-forest-ink       { background: #1f2a24 url("../assets/screenshot-backgrounds/style-a/forest-ink.webp")       center/cover no-repeat; }
+    .frame-shot.bg-asset-indigo-porcelain { background: #cfd6dd url("../assets/screenshot-backgrounds/style-a/indigo-porcelain.webp") center/cover no-repeat; }
+    .frame-shot.bg-asset-kraft-paper      { background: #c9a983 url("../assets/screenshot-backgrounds/style-a/kraft-paper.webp")      center/cover no-repeat; }
+    .frame-shot.bg-asset-monocle-classic  { background: #e8e1d4 url("../assets/screenshot-backgrounds/style-a/monocle-classic.webp")  center/cover no-repeat; }
+
     /* padding wraps the inner shot — content gets to "float" on the bg tone */
     .frame-shot.inset-none > img,
     .frame-shot.inset-none > .shot-body { padding: 0; }

assets/template-swiss-card.html

@@ -118,6 +118,7 @@
     .poster.xhs    { width: 1080px; height: 1440px; }
     .poster.square { width: 1080px; height: 1080px; }
     .poster.wide   { width: 2100px; height:  900px; }
+    .poster figure { margin: 0; }
 
     .poster.xhs    .content { padding: var(--sp-12) var(--sp-11); }
     .poster.square .content { padding: var(--sp-11) var(--sp-11); }
@@ -410,6 +411,13 @@
       background-size: 18px 18px;
     }
 
+    /* asset backgrounds — ported from PPT skill, real texture for screenshot wells.
+       Use ONLY when current accent matches the asset's accent (don't mix oranges and IKB). */
+    .frame-shot.bg-asset-ikb-dot          { background: #0c1a3a url("../assets/screenshot-backgrounds/style-b/ikb-dot-gradient.webp")       center/cover no-repeat; }
+    .frame-shot.bg-asset-lemon-green-dot  { background: #d6e08a url("../assets/screenshot-backgrounds/style-b/lemon-green-dot-shadow.webp") center/cover no-repeat; }
+    .frame-shot.bg-asset-lemon-grid       { background: #e6e9b8 url("../assets/screenshot-backgrounds/style-b/lemon-grid.webp")             center/cover no-repeat; }
+    .frame-shot.bg-asset-safety-orange    { background: #ff5b1f url("../assets/screenshot-backgrounds/style-b/safety-orange-halftone.webp") center/cover no-repeat; }
+
     .frame-shot.inset-none > img,
     .frame-shot.inset-none > .shot-body { padding: 0; }
     .frame-shot.inset-sub  { padding: 20px; }