fix(years): format academic years as 2016/17 across all views, remove legacy frontend and data

Apply formatAcademicYear to all year displays in ComparisonChart, ComparisonView,
PerformanceChart, and RankingsView. Remove old vanilla JS frontend and CSV data
directory — both superseded by the Next.js app and Meltano pipeline.

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

nextjs-app/components/ComparisonChart.tsx

@@ -18,7 +18,7 @@ import {
   ChartOptions,
 } from 'chart.js';
 import type { ComparisonData } from '@/lib/types';
-import { CHART_COLORS } from '@/lib/utils';
+import { CHART_COLORS, formatAcademicYear } from '@/lib/utils';
 
 // Register Chart.js components
 ChartJS.register(
@@ -68,7 +68,7 @@ export function ComparisonChart({ comparisonData, metric, metricLabel }: Compari
   });
 
   const chartData = {
-    labels: years.map(String),
+    labels: years.map(formatAcademicYear),
     datasets,
   };
 

nextjs-app/components/ComparisonView.tsx

@@ -13,7 +13,7 @@ import { SchoolSearchModal } from './SchoolSearchModal';
 import { EmptyState } from './EmptyState';
 import { LoadingSkeleton } from './LoadingSkeleton';
 import type { ComparisonData, MetricDefinition, School } from '@/lib/types';
-import { formatPercentage, formatProgress, CHART_COLORS, schoolUrl } from '@/lib/utils';
+import { formatPercentage, formatProgress, formatAcademicYear, CHART_COLORS, schoolUrl } from '@/lib/utils';
 import { fetchComparison } from '@/lib/api';
 import styles from './ComparisonView.module.css';
 
@@ -392,7 +392,7 @@ export function ComparisonView({
                   <tbody>
                     {years.map((year) => (
                       <tr key={year}>
-                        <td className={styles.yearCell}>{year}</td>
+                        <td className={styles.yearCell}>{formatAcademicYear(year)}</td>
                         {activeSchools.map((school) => {
                           const schoolData = activeComparisonData[school.urn];
                           if (!schoolData) return <td key={school.urn}>-</td>;

nextjs-app/components/PerformanceChart.tsx

@@ -18,6 +18,7 @@ import {
   ChartOptions,
 } from 'chart.js';
 import type { SchoolResult } from '@/lib/types';
+import { formatAcademicYear } from '@/lib/utils';
 import styles from './PerformanceChart.module.css';
 
 // Register Chart.js components
@@ -40,11 +41,7 @@ interface PerformanceChartProps {
 export function PerformanceChart({ data, schoolName, isSecondary = false }: PerformanceChartProps) {
   // Sort data by year
   const sortedData = [...data].sort((a, b) => a.year - b.year);
-  const formatYear = (y: number) => {
-    const s = y.toString();
-    return s.length === 6 ? `${s.slice(0, 4)}/${s.slice(4)}` : s;
-  };
-  const years = sortedData.map(d => formatYear(d.year));
+  const years = sortedData.map(d => formatAcademicYear(d.year));
 
   // Prepare datasets — phase-aware
   const datasets = isSecondary ? [

nextjs-app/components/RankingsView.tsx

@@ -8,7 +8,7 @@
 import { useRouter, usePathname, useSearchParams } from 'next/navigation';
 import { useComparison } from '@/hooks/useComparison';
 import type { RankingEntry, Filters, MetricDefinition } from '@/lib/types';
-import { formatPercentage, formatProgress, schoolUrl } from '@/lib/utils';
+import { formatPercentage, formatProgress, formatAcademicYear, schoolUrl } from '@/lib/utils';
 import { EmptyState } from './EmptyState';
 import styles from './RankingsView.module.css';
 
@@ -199,11 +199,11 @@ export function RankingsView({
             className={styles.filterSelect}
           >
             <option value="">
-              {filters.years.length > 0 ? `${Math.max(...filters.years)} (Latest)` : 'Latest'}
+              {filters.years.length > 0 ? `${formatAcademicYear(Math.max(...filters.years))} (Latest)` : 'Latest'}
             </option>
             {filters.years.map((year) => (
               <option key={year} value={year}>
-                {year}
+                {formatAcademicYear(year)}
               </option>
             ))}
           </select>