feat(cms): 品牌叙事与结构性文案全站 CMS 化并补齐信任证据阶段 0

- 品牌叙事内核（价值主张/定位/承诺/三支柱/语气）下沉 site-config，经 SiteConfigProvider 注入全站
- 新增 page-copy 内容模型承载结构性文案（章节标题/眉标/描述/CTA/空状态），覆盖首页+服务/方案/产品/案例/新闻列表页，「CMS 优先 + 硬编码兜底」不白屏
- 首页「首批客户共创计划」板块（earlyAccessTitle/CtaLabel/Status 驱动）替代单行标签，如实呈现共创/内测/授权公开三档状态
- 关于页资质区数据空时如实展示「建设中」空态
- 零编造：不虚构客户/数据/资质

src/app/layout.tsx

@@ -15,7 +15,7 @@ import { BackToTop } from "@/components/ui/back-to-top";
 import { ClientLayout } from "@/components/layout/client-layout";
 import { getPublishedItems } from "@/lib/cms/data-server";
 import { SiteConfigProvider, type SiteConfig, type NavigationItem, type MegaDropdownGroup, type MegaDropdownItem } from "@/lib/site-config";
-import { COMPANY_INFO } from "@/lib/constants/company";
+import { COMPANY_INFO, BRAND_NARRATIVE, type BrandPillar } from "@/lib/constants/company";
 import { NAVIGATION_V2, MEGA_DROPDOWN_DATA } from "@/lib/constants/navigation";
 
 export const metadata: Metadata = {
@@ -127,6 +127,11 @@ export default async function RootLayout({
     displayName: (configData?.displayName as string) || COMPANY_INFO.displayName,
     slogan: (configData?.slogan as string) || COMPANY_INFO.slogan,
     description: (configData?.description as string) || COMPANY_INFO.description,
+    valueProposition: (configData?.valueProposition as string) || BRAND_NARRATIVE.valueProposition,
+    positioningStatement: (configData?.positioningStatement as string) || BRAND_NARRATIVE.positioningStatement,
+    brandPromise: (configData?.brandPromise as string) || BRAND_NARRATIVE.brandPromise,
+    toneOfVoice: (configData?.toneOfVoice as string) || BRAND_NARRATIVE.toneOfVoice,
+    pillars: (Array.isArray(configData?.pillars) ? configData.pillars : BRAND_NARRATIVE.pillars) as BrandPillar[],
     founded: (configData?.founded as string) || COMPANY_INFO.founded,
     location: (configData?.location as string) || COMPANY_INFO.location,
     email: (configData?.email as string) || COMPANY_INFO.email,