Add expandable rating history charts with interactive tooltips

- Implement clickable player rows to expand/collapse rating history
- Add rating history scraping from PDGA history pages
- Create custom SVG line charts showing rating progression over time
- Add interactive tooltips with date and rating on hover
- Include visual highlights when hovering over data points
- Implement anti-flicker tooltip system with delayed hiding
- Add large hover areas (12px radius) for better user experience
- Show grid lines, axis labels, and responsive chart scaling
- Cache rating history data to avoid repeated API calls

🤖 Generated with [Claude Code](https://claude.ai/code)

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

server.js

@@ -423,6 +423,109 @@ app.get('/api/ratings/progress', (req, res) => {
   });
 });
 
+async function fetchRatingHistory(pdgaNumber) {
+  return new Promise((resolve, reject) => {
+    const options = {
+      hostname: 'www.pdga.com',
+      port: 443,
+      path: `/player/${pdgaNumber}/history`,
+      method: 'GET',
+      headers: {
+        'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36'
+      },
+      timeout: 30000
+    };
+
+    const req = https.request(options, (res) => {
+      let data = '';
+      res.on('data', (chunk) => {
+        data += chunk;
+      });
+      
+      res.on('end', () => {
+        if (res.statusCode === 200) {
+          resolve(data);
+        } else {
+          reject(new Error(`HTTP ${res.statusCode}`));
+        }
+      });
+    });
+
+    req.on('error', (error) => {
+      reject(error);
+    });
+
+    req.on('timeout', () => {
+      req.destroy();
+      reject(new Error('Request timeout'));
+    });
+
+    req.setTimeout(30000);
+    req.end();
+  });
+}
+
+function parseRatingHistory(html) {
+  const history = [];
+  
+  // Find all table rows with rating data
+  const rowMatches = html.match(/<tr[^>]*>[\s\S]*?<\/tr>/gi);
+  
+  if (rowMatches) {
+    for (const row of rowMatches) {
+      // Skip header rows and empty rows
+      if (row.includes('<th') || !row.includes('<td')) continue;
+      
+      // Extract date, rating, and rounds from table cells
+      const cellMatches = row.match(/<td[^>]*>(.*?)<\/td>/gi);
+      
+      if (cellMatches && cellMatches.length >= 2) {
+        const dateText = cellMatches[0].replace(/<[^>]*>/g, '').trim();
+        const ratingText = cellMatches[1].replace(/<[^>]*>/g, '').trim();
+        
+        // Parse date (DD-Mon-YYYY format)
+        const dateMatch = dateText.match(/(\d{1,2})-([A-Za-z]{3})-(\d{4})/);
+        if (dateMatch && !isNaN(parseInt(ratingText))) {
+          const [, day, month, year] = dateMatch;
+          const monthMap = {
+            'Jan': 0, 'Feb': 1, 'Mar': 2, 'Apr': 3, 'May': 4, 'Jun': 5,
+            'Jul': 6, 'Aug': 7, 'Sep': 8, 'Oct': 9, 'Nov': 10, 'Dec': 11
+          };
+          
+          const date = new Date(parseInt(year), monthMap[month], parseInt(day));
+          
+          history.push({
+            date: date.toISOString().split('T')[0], // YYYY-MM-DD format
+            rating: parseInt(ratingText),
+            displayDate: dateText
+          });
+        }
+      }
+    }
+  }
+  
+  // Sort by date (oldest first for chart display)
+  return history.sort((a, b) => new Date(a.date) - new Date(b.date));
+}
+
+app.get('/api/rating-history/:pdgaNumber', async (req, res) => {
+  try {
+    const { pdgaNumber } = req.params;
+    console.log(`Fetching rating history for PDGA ${pdgaNumber}...`);
+    
+    const html = await fetchRatingHistory(pdgaNumber);
+    const history = parseRatingHistory(html);
+    
+    res.json({ 
+      pdgaNumber: parseInt(pdgaNumber),
+      history 
+    });
+  } catch (error) {
+    console.error('Error fetching rating history:', error.message);
+    res.status(500).json({ error: 'Failed to fetch rating history' });
+  }
+});
+
 app.post('/api/predicted-rating/:pdgaNumber', async (req, res) => {
   let browser = null;
   try {