feat(ux): implement comprehensive UX audit fixes across all pages

Addresses 28 issues identified in UX audit (P0–P3 severity):

P0 — Critical:
- Fix compare URL sharing: seed ComparisonContext from SSR initialData
  when localStorage is empty, making /compare?urns=... links shareable
- Remove permanently broken "Avg. Scaled Score" column from school
  detail historical data table

P1 — High priority:
- Add radius selector (0.5–10 mi) to postcode search in FilterBar
- Make Add to Compare a toggle (remove) on SchoolCards
- Hide hero title/description once a search is active
- Show school count + quick-search prompts on empty landing page
- Compare empty state opens in-page school search modal directly
- Remove URN from school detail header (irrelevant to end users)
- Move map above performance chart in school detail page
- Add ← Back navigation to school detail page
- Add sort controls to search results (RWM%, distance, A–Z)
- Show metric descriptions below metric selector
- Expand ComparisonToast to list school names with per-school remove
- Add progress score explainer (0 = national average) throughout

P2 — Medium:
- Remove console.log statements from ComparisonView
- Colour-code comparison school cards to match chart line colours
- Replace plain loading text with LoadingSkeleton in ComparisonView
- Rankings empty state uses shared EmptyState component
- Rankings year filter shows actual year e.g. "2023 (Latest)"
- Rankings subtitle shows top-N count
- Add View link alongside Add button in rankings table
- Remove placeholder Privacy Policy / Terms links from footer
- Replace untappable 10px info icons with visible metric hint text
- Show active filter chips in search results header

P3 — Polish:
- Remove redundant "Home" nav link (logo already links home)
- Add / and Ctrl+K keyboard shortcut to focus search input
- Add Share button to compare page (copies URL to clipboard)

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

nextjs-app/components/HomeView.tsx

@@ -19,13 +19,15 @@ import styles from './HomeView.module.css';
 interface HomeViewProps {
   initialSchools: SchoolsResponse;
   filters: Filters;
+  totalSchools?: number | null;
 }
 
-export function HomeView({ initialSchools, filters }: HomeViewProps) {
+export function HomeView({ initialSchools, filters, totalSchools }: HomeViewProps) {
   const searchParams = useSearchParams();
-  const { addSchool, selectedSchools } = useComparisonContext();
+  const { addSchool, removeSchool, selectedSchools } = useComparisonContext();
   const [resultsView, setResultsView] = useState<'list' | 'map'>('list');
   const [selectedMapSchool, setSelectedMapSchool] = useState<School | null>(null);
+  const [sortOrder, setSortOrder] = useState<string>('default');
 
   const hasSearch = searchParams.get('search') || searchParams.get('postcode');
   const isLocationSearch = !!searchParams.get('postcode');
@@ -36,19 +38,43 @@ export function HomeView({ initialSchools, filters }: HomeViewProps) {
     setSelectedMapSchool(null);
   }, [resultsView, searchParams]);
 
+  const sortedSchools = [...initialSchools.schools].sort((a, b) => {
+    if (sortOrder === 'rwm_desc') return (b.rwm_expected_pct ?? -Infinity) - (a.rwm_expected_pct ?? -Infinity);
+    if (sortOrder === 'rwm_asc') return (a.rwm_expected_pct ?? Infinity) - (b.rwm_expected_pct ?? Infinity);
+    if (sortOrder === 'distance') return (a.distance ?? Infinity) - (b.distance ?? Infinity);
+    if (sortOrder === 'name_asc') return a.school_name.localeCompare(b.school_name);
+    return 0;
+  });
+
   return (
     <div className={styles.homeView}>
       {/* Combined Hero + Search and Filters */}
-      <div className={styles.heroSection}>
-        <h1 className={styles.heroTitle}>Compare Primary School Performance</h1>
-        <p className={styles.heroDescription}>Search and compare KS2 results for thousands of schools across England</p>
-      </div>
-      
+      {!isSearchActive && (
+        <div className={styles.heroSection}>
+          <h1 className={styles.heroTitle}>Compare Primary School Performance</h1>
+          <p className={styles.heroDescription}>Search and compare KS2 results for thousands of schools across England</p>
+        </div>
+      )}
+
       <FilterBar
         filters={filters}
         isHero={!isSearchActive}
       />
 
+      {/* Discovery section shown on landing page before any search */}
+      {!isSearchActive && initialSchools.schools.length === 0 && (
+        <div className={styles.discoverySection}>
+          {totalSchools && <p className={styles.discoveryCount}><strong>{totalSchools.toLocaleString()}+</strong> primary schools across England</p>}
+          <p className={styles.discoveryHints}>Try searching for a school name, or enter a postcode to find schools near you.</p>
+          <div className={styles.quickSearches}>
+            <span className={styles.quickSearchLabel}>Quick searches:</span>
+            {['Manchester', 'Bristol', 'Leeds', 'Birmingham'].map(city => (
+              <a key={city} href={`/?search=${city}`} className={styles.quickSearchChip}>{city}</a>
+            ))}
+          </div>
+        </div>
+      )}
+
       {/* Location Info Banner with View Toggle */}
       {isLocationSearch && initialSchools.location_info && (
         <div className={styles.locationBannerWrapper}>
@@ -106,6 +132,22 @@ export function HomeView({ initialSchools, filters }: HomeViewProps) {
               {initialSchools.total.toLocaleString()} school
               {initialSchools.total !== 1 ? 's' : ''} found
             </h2>
+            <select value={sortOrder} onChange={e => setSortOrder(e.target.value)} className={styles.sortSelect}>
+              <option value="default">Sort: Relevance</option>
+              <option value="rwm_desc">Highest RWM%</option>
+              <option value="rwm_asc">Lowest RWM%</option>
+              {isLocationSearch && <option value="distance">Nearest first</option>}
+              <option value="name_asc">Name A–Z</option>
+            </select>
+          </div>
+        )}
+
+        {isSearchActive && (
+          <div className={styles.activeFilters}>
+            {searchParams.get('search') && <span className={styles.filterChip}>Search: {searchParams.get('search')}<a href="/" className={styles.chipRemove} onClick={e => { e.preventDefault(); }}>×</a></span>}
+            {searchParams.get('local_authority') && <span className={styles.filterChip}>{searchParams.get('local_authority')}</span>}
+            {searchParams.get('school_type') && <span className={styles.filterChip}>{searchParams.get('school_type')}</span>}
+            {searchParams.get('postcode') && <span className={styles.filterChip}>Near {searchParams.get('postcode')} ({(parseFloat(searchParams.get('radius') || '1.6') / 1.60934).toFixed(1)} mi)</span>}
           </div>
         )}
 
@@ -132,8 +174,8 @@ export function HomeView({ initialSchools, filters }: HomeViewProps) {
             </div>
             <div className={styles.compactList}>
               {initialSchools.schools.map((school) => (
-                <div 
-                  key={school.urn} 
+                <div
+                  key={school.urn}
                   className={`${styles.listItemWrapper} ${selectedMapSchool?.urn === school.urn ? styles.highlightedItem : ''}`}
                 >
                   <CompactSchoolItem
@@ -163,11 +205,12 @@ export function HomeView({ initialSchools, filters }: HomeViewProps) {
           /* List View Layout */
           <>
             <div className={styles.grid}>
-              {initialSchools.schools.map((school) => (
+              {sortedSchools.map((school) => (
                 <SchoolCard
                   key={school.urn}
                   school={school}
                   onAddToCompare={addSchool}
+                  onRemoveFromCompare={removeSchool}
                   isInCompare={selectedSchools.some(s => s.urn === school.urn)}
                 />
               ))}