feat(docs): Google 'Add to preferred sources' button in the site footer

docs/.vitepress/config.ts

@@ -27,6 +27,7 @@ export default defineConfig({
     ['meta', { httpEquiv: 'Origin-Trial', content: ORIGIN_TRIAL_WEBMCP }],
     ['script', { src: '/neuron-js/webmcp/webmcp.js' }],
     ['script', { src: '/neuron-js/webmcp/neuron-webmcp.js', defer: 'true' }],
+    ['script', { async: 'true', src: 'https://news.google.com/swg/js/v1/publisher.js' }],
   ],
   ignoreDeadLinks: true,
   markdown: {

docs/.vitepress/theme/PreferredSourceFooter.vue

@@ -0,0 +1,40 @@
+<template>
+  <div class="preferred-source-footer">
+    <div google-add-preferred-source-btn :data-theme="isDark ? 'dark' : 'light'"></div>
+    <p class="preferred-source-note">
+      Add <code>sebasoft.github.io</code> as a preferred source in Google Search — Top Stories,
+      AI Overviews, and AI Mode.
+    </p>
+  </div>
+</template>
+
+<script setup lang="ts">
+import { useData } from "vitepress";
+
+const { isDark } = useData();
+</script>
+
+<style scoped>
+.preferred-source-footer {
+  align-items: center;
+  border-top: 1px solid var(--vp-c-divider);
+  display: flex;
+  flex-direction: column;
+  gap: 8px;
+  margin: 24px auto 0;
+  max-width: 768px;
+  padding: 16px 24px 8px;
+}
+
+.preferred-source-footer > div {
+  min-height: 40px;
+}
+
+.preferred-source-note {
+  color: var(--vp-c-text-2);
+  font-size: 13px;
+  line-height: 1.5;
+  margin: 0;
+  text-align: center;
+}
+</style>

docs/.vitepress/theme/index.ts

@@ -1,7 +1,9 @@
 import DefaultTheme from "vitepress/theme";
 import { inBrowser } from "vitepress";
 import type { EnhanceAppContext } from "vitepress";
+import { h } from "vue";
 import mermaid from "mermaid";
+import PreferredSourceFooter from "./PreferredSourceFooter.vue";
 import "./custom.css";
 
 const isDarkMode = () => document.documentElement.classList.contains("dark");
@@ -56,6 +58,11 @@ const scheduleRender = () => {
 
 export default {
   extends: DefaultTheme,
+  Layout() {
+    return h(DefaultTheme.Layout, null, {
+      "layout-bottom": () => h(PreferredSourceFooter),
+    });
+  },
   enhanceApp({ router }: EnhanceAppContext) {
     if (!inBrowser) {
       return;
@@ -68,6 +75,9 @@ export default {
     router.onAfterRouteChanged = async (to) => {
       await afterRouteChange?.(to);
       scheduleRender();
+      // The Google preferred-source button lives in the layout-bottom slot,
+      // which VitePress keeps mounted across SPA route changes; publisher.js
+      // initializes it once on load — verified in the browser E2E.
     };
   },
   setup() {

tests/contracts/preferred-source-footer.test.ts

@@ -0,0 +1,33 @@
+// NJS-SEO-6 follow-up: contract test for the Google "Add to preferred sources"
+// footer button on the documentation site.
+import { readFileSync } from "node:fs";
+import { describe, expect, it } from "vitest";
+
+const read = (path: string) => readFileSync(path, "utf8");
+
+describe("Google preferred-source footer button", () => {
+  it("loads the official publisher.js in the VitePress head", () => {
+    expect(read("docs/.vitepress/config.ts")).toContain(
+      "https://news.google.com/swg/js/v1/publisher.js",
+    );
+  });
+
+  it("renders the standard button container in the layout-bottom footer", () => {
+    const component = read("docs/.vitepress/theme/PreferredSourceFooter.vue");
+    expect(component).toContain("google-add-preferred-source-btn");
+    expect(component).toContain("preferred-source-footer");
+    // theme aware: light/dark follows the site theme
+    expect(component).toContain("isDark");
+  });
+
+  it("mounts the footer via the layout-bottom slot", () => {
+    const theme = read("docs/.vitepress/theme/index.ts");
+    expect(theme).toContain("PreferredSourceFooter");
+    expect(theme).toContain("layout-bottom");
+  });
+
+  it("states the eligible source honestly (domain, not subdirectory)", () => {
+    const component = read("docs/.vitepress/theme/PreferredSourceFooter.vue");
+    expect(component).toContain("sebasoft.github.io");
+  });
+});