site-builder: dynamic CTAs, section anchors, edit-with-Sitesmith

Three related features:

1. Dynamic CTA buttons on HeroSimple, CTASection, CallToAction.
   New shared ctas[] array (text + href + variant + target) replaces the
   primary/secondary pair. Settings panel gets add/remove/reorder controls.
   Legacy fields stay readable for backwards compat — first user edit
   migrates the section onto the new array.

2. Anchor IDs on all layout/section components (Container, Section,
   BackgroundSection, ColumnLayout, plus 6 section blocks done by parallel
   subagent, plus Hero/CTA/CallToAction). Anchor input lives in the
   settings panel with an "auto from heading" button that walks the
   subtree for the first Heading.text. Renders as id="..." on the
   outermost element so #anchor URLs resolve.

3. Edit-with-Sitesmith targeted invocation. Right-click → "Ask Sitesmith"
   and a button at the top of the right-side settings panel both open the
   modal pre-targeted at the selected node. The node's serialized subtree
   is sent to the server; system prompt is augmented to require a patch
   with replace_node. Editor lifts modal state into a new SitesmithContext.

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

craft/src/App.tsx

@@ -6,18 +6,29 @@ import { WhpConfig } from './types';
 import { EditorConfigProvider } from './state/EditorConfigContext';
 import { SiteDesignProvider } from './state/SiteDesignContext';
 import { PageProvider } from './state/PageContext';
+import { SitesmithProvider, useSitesmithModal } from './state/SitesmithContext';
+import { SitesmithModal } from './panels/sitesmith/SitesmithModal';
 
 interface AppProps {
   whpConfig: WhpConfig | null;
 }
 
+const SitesmithModalMount: React.FC = () => {
+  const { isOpen, target, close } = useSitesmithModal();
+  if (!isOpen) return null;
+  return <SitesmithModal target={target} onClose={close} />;
+};
+
 export const App: React.FC<AppProps> = ({ whpConfig }) => {
   return (
     <EditorConfigProvider config={whpConfig}>
       <SiteDesignProvider>
         <Editor resolver={componentResolver} enabled={true}>
           <PageProvider>
-            <EditorShell />
+            <SitesmithProvider>
+              <EditorShell />
+              <SitesmithModalMount />
+            </SitesmithProvider>
           </PageProvider>
         </Editor>
       </SiteDesignProvider>