feat(site-builder): per-page SEO meta + favicon + design-token CSS-var wiring + published-output a11y/perf

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

craft/src/state/PageContext.tsx

@@ -1,6 +1,6 @@
 import React, { createContext, useContext, useState, useCallback, useRef, ReactNode } from 'react';
 import { useEditor } from '@craftjs/core';
-import { PageData } from '../types';
+import { PageData, PageSeo } from '../types';
 import { SerializedTreeNode } from '../types/sitesmith';
 import { useSiteDesign, SiteDesign } from './SiteDesignContext';
 import { sanitizeAiTree, flattenTreeForCraft, FlatCraftNode } from '../utils/craft-tree';
@@ -18,9 +18,11 @@ interface PageContextValue {
   addPage: (name: string, slug: string) => void;
   deletePage: (pageId: string) => void;
   renamePage: (pageId: string, name: string, slug: string) => void;
+  /** Merges `seo` fields onto the target page's existing `seo` (creating it if absent). */
+  updatePageSeo: (pageId: string, seo: Partial<PageSeo>) => void;
   setHeaderCraftState: (craftState: string) => void;
   setFooterCraftState: (craftState: string) => void;
-  setPagesCraftState: (pagesData: { id: string; name: string; slug: string; craftState: string | null }[]) => void;
+  setPagesCraftState: (pagesData: { id: string; name: string; slug: string; craftState: string | null; seo?: PageSeo }[]) => void;
   /**
    * Bookkeeping-only: point `activePageId` at an already-loaded page without
    * re-serializing/deserializing the canvas (the caller -- e.g. useWhpApi's
@@ -186,6 +188,7 @@ const PageContext = createContext<PageContextValue>({
   addPage: () => {},
   deletePage: () => {},
   renamePage: () => {},
+  updatePageSeo: () => {},
   setHeaderCraftState: () => {},
   setFooterCraftState: () => {},
   setPagesCraftState: () => {},
@@ -421,6 +424,13 @@ export const PageProvider: React.FC<{ children: ReactNode }> = ({ children }) =>
     );
   }, []);
 
+  /** Merges `seo` fields onto the target page's existing `seo` (creating it if absent). */
+  const updatePageSeo = useCallback((pageId: string, seo: Partial<PageSeo>) => {
+    setPages((prev) =>
+      prev.map((p) => (p.id === pageId ? { ...p, seo: { ...p.seo, ...seo } } : p)),
+    );
+  }, []);
+
   /** Allow external code (e.g., load from API) to set the header craft state */
   const setHeaderCraftState = useCallback((craftState: string) => {
     setHeaderPage((prev) => ({ ...prev, craftState }));
@@ -442,7 +452,7 @@ export const PageProvider: React.FC<{ children: ReactNode }> = ({ children }) =>
   }, []);
 
   /** Allow external code (e.g., load from API) to restore pages with craft states */
-  const setPagesCraftState = useCallback((pagesData: { id: string; name: string; slug: string; craftState: string | null }[]) => {
+  const setPagesCraftState = useCallback((pagesData: { id: string; name: string; slug: string; craftState: string | null; seo?: PageSeo }[]) => {
     setPages(pagesData.map((p, i) => ({
       id: p.id,
       name: p.name,
@@ -451,6 +461,7 @@ export const PageProvider: React.FC<{ children: ReactNode }> = ({ children }) =>
       // ALWAYS the landing page → slug 'index' → file index.html.
       slug: i === 0 ? 'index' : p.slug,
       craftState: p.craftState,
+      seo: p.seo,
     })));
   }, []);
 
@@ -545,6 +556,7 @@ export const PageProvider: React.FC<{ children: ReactNode }> = ({ children }) =>
         addPage,
         deletePage,
         renamePage,
+        updatePageSeo,
         setHeaderCraftState,
         setFooterCraftState,
         setPagesCraftState,