analytics: add neeldhara analytics script to BaseHead

Single defer'd <script> in BaseHead so it lands on every page
(homepage, theme pages, full interactives, embeds, admin, blog).
is:inline keeps Astro from processing it.

https://claude.ai/code/session_01KNdXjQczMCRGMK7K3Qderw

src/components/BaseHead.astro

@@ -114,3 +114,10 @@ const imageURL = new URL(finalImage, Astro.site);
 <meta property="twitter:description" content={finalDescription} />
 <meta property="twitter:image" content={imageURL} />
 <meta property="twitter:creator" content={SITE_METADATA.twitter.creator} />
+
+<!-- Analytics -->
+<script
+  is:inline
+  src="https://analytics.neeldhara.website/api/script.js"
+  data-site-id="667a0b3abc8a"
+  defer></script>