Task 4: Add PatientBanner component with full/condensed modes

- Create useScrollCondensation hook with IntersectionObserver
- PatientBanner with 80px full mode and 48px condensed mode
- Smooth height transition (200ms) on scroll past 100px
- Status dot (green) and badge for 'Open to opportunities'
- Action buttons: Download CV, Email, LinkedIn
- NHS blue outlined buttons with hover fill effect
- Proper GPhC number formatting with tooltip
- Sticky positioning for persistent visibility

src/hooks/useScrollCondensation.ts

@@ -0,0 +1,35 @@
+import { useState, useEffect, useRef } from 'react'
+
+interface UseScrollCondensationOptions {
+  threshold?: number
+}
+
+export function useScrollCondensation(options: UseScrollCondensationOptions = {}) {
+  const { threshold = 100 } = options
+  const [isCondensed, setIsCondensed] = useState(false)
+  const sentinelRef = useRef<HTMLDivElement>(null)
+
+  useEffect(() => {
+    const sentinel = sentinelRef.current
+    if (!sentinel) return
+
+    const observer = new IntersectionObserver(
+      (entries) => {
+        const [entry] = entries
+        setIsCondensed(!entry.isIntersecting)
+      },
+      {
+        rootMargin: `-${threshold}px 0px 0px 0px`,
+        threshold: 0,
+      }
+    )
+
+    observer.observe(sentinel)
+
+    return () => {
+      observer.disconnect()
+    }
+  }, [threshold])
+
+  return { isCondensed, sentinelRef }
+}