Initial commit: React frontend (SLP Software) + AIDLC workflow docs

Co-authored-by: Junie <junie@jetbrains.com>

src/utils/scrollToHash.ts

@@ -0,0 +1,29 @@
+import type { MouseEvent } from 'react';
+
+/**
+ * Smoothly scrolls to the element matching the given in-page anchor (e.g. "#pakketten").
+ *
+ * The app uses hash-based routing (see src/router.tsx) so plain `<a href="#id">` links
+ * would otherwise be intercepted by the router as a path change, which resets the URL
+ * hash back to "/" right after the browser's native anchor scroll. That causes the
+ * "scrolls correctly, then jumps back to top on the next click" behaviour. Intercepting
+ * the click and scrolling manually (without touching the URL hash) avoids the conflict.
+ */
+export function scrollToHash(hash: string) {
+  const id = hash.replace(/^#/, '');
+  const target = document.getElementById(id);
+  target?.scrollIntoView({ behavior: 'smooth', block: 'start' });
+}
+
+/**
+ * Click handler for in-page anchor links. Prevents the default hash navigation
+ * (which would conflict with the app's hash-based router) and scrolls smoothly instead.
+ */
+export function handleAnchorClick(event: MouseEvent<HTMLAnchorElement>, href: string) {
+  if (!href.startsWith('#')) {
+    return;
+  }
+
+  event.preventDefault();
+  scrollToHash(href);
+}