US-001: Remove unused legacy components and hooks

Delete 23 dead files: old portfolio components (Contact, Education,
Experience, FloatingNav, Footer, Hero, Projects, Skills), legacy PMR
components (PMRInterface, PatientBanner, ClinicalSidebar, Breadcrumb,
MobileBottomNav), all 7 views/ directory files, and 3 unused hooks
(useScrollCondensation, useActiveSection, useScrollReveal).

No imports referenced any of these files — clean removal with zero
build or type errors.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/hooks/useActiveSection.ts

@@ -1,58 +0,0 @@
-import { useEffect, useState, useRef, useCallback } from 'react'
-
-const SECTION_IDS = ['about', 'skills', 'experience', 'education', 'projects', 'contact'] as const
-
-type SectionId = typeof SECTION_IDS[number]
-
-export function useActiveSection(): SectionId {
-  const [activeSection, setActiveSection] = useState<SectionId>('about')
-  const observerRef = useRef<IntersectionObserver | null>(null)
-  const visibleSectionsRef = useRef<Map<string, number>>(new Map())
-
-  const handleIntersect = useCallback((entries: IntersectionObserverEntry[]) => {
-    entries.forEach((entry) => {
-      const sectionId = entry.target.id
-      if (SECTION_IDS.includes(sectionId as SectionId)) {
-        if (entry.isIntersecting) {
-          visibleSectionsRef.current.set(sectionId, entry.intersectionRatio)
-        } else {
-          visibleSectionsRef.current.delete(sectionId)
-        }
-      }
-    })
-
-    const visibleEntries = Array.from(visibleSectionsRef.current.entries())
-    if (visibleEntries.length > 0) {
-      visibleEntries.sort((a, b) => {
-        const indexA = SECTION_IDS.indexOf(a[0] as SectionId)
-        const indexB = SECTION_IDS.indexOf(b[0] as SectionId)
-        return indexA - indexB
-      })
-      
-      const topSection = visibleEntries[0][0] as SectionId
-      setActiveSection(topSection)
-    }
-  }, [])
-
-  useEffect(() => {
-    observerRef.current = new IntersectionObserver(handleIntersect, {
-      rootMargin: '-20% 0px -70% 0px',
-      threshold: [0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1],
-    })
-
-    SECTION_IDS.forEach((id) => {
-      const element = document.getElementById(id)
-      if (element && observerRef.current) {
-        observerRef.current.observe(element)
-      }
-    })
-
-    return () => {
-      if (observerRef.current) {
-        observerRef.current.disconnect()
-      }
-    }
-  }, [handleIntersect])
-
-  return activeSection
-}