Remove website modal and use cookbook detail routes (#2312)

- replace cookbook recipe/example modal views with dedicated detail pages
- add legacy #file cookbook hash redirects to canonical routes
- remove modal component/runtime and associated CSS and stale page references

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Copilot-Session: ca1a64ec-678f-45ac-ba68-33a37717398a

website/src/pages/index.astro

@@ -1,6 +1,5 @@
 ---
 import StarlightPage from "@astrojs/starlight/components/StarlightPage.astro";
-import Modal from "../components/Modal.astro";
 import Icon from "../components/Icon.astro";
 import BackToTop from "../components/BackToTop.astro";
 
@@ -177,8 +176,6 @@ const base = import.meta.env.BASE_URL;
     </section>
   </div>
 
-  <Modal />
-
   <!-- Back to Top Button -->
   <BackToTop />