Add deduplication and normalize names/URLs

Add product name cleanup and URL normalization across backend, scrapers, and frontend; introduce product/event deduplication. Key changes:
- Clean up SVG/CSS garbage, trailing "X Reviews", mojibake and extra spaces in product names (api, scrapers, JS).
- Normalize URLs (lowercase host, strip tracking/query params, trim trailing slashes) in scrapers and Database and use normalized URL for comparisons/storage.
- Database: use normalized URLs when creating/getting products, prevent duplicate stock events within 1 hour, adjust recent events query to avoid duplicate products.
- Implement deduplication routines in Database: deduplicate_products (by product_id and normalized/clean name) and deduplicate_events (remove duplicate events within same hour).
- API: add POST endpoints /products/deduplicate and /events/deduplicate to trigger deduplication and return stats.
- Frontend: add UI buttons and handlers to call deduplication endpoints and display results.

These changes reduce duplicate product records/events caused by minor URL/name variations and stray CSS/svg artifacts.

dashboard/static/app.js

@@ -674,6 +674,11 @@ function cleanProductName(name) {
 
   // Fix common UTF-8 encoding issues (mojibake)
   return name
+    // Remove SVG/CSS class garbage (pikachu_svg__st1{fill:#7c888f}.review-full-...)
+    .replace(/[\w-]*_svg__[\w\s{}:#.;-]+/gi, '')
+    .replace(/\.review-full-[\w\s{}:#.;-]+/gi, '')
+    .replace(/\{[^}]*\}/g, '')  // Remove any remaining {css} blocks
+    .replace(/\d+\s*Reviews?$/i, '')  // Remove trailing "X Reviews"
     // Fix Pokémon - multiple encoding patterns
     .replace(/Pok[éÃ\u00c3\u00a9]+mon/gi, 'Pokémon')
     .replace(/Pokémon/gi, 'Pokémon')
@@ -1278,6 +1283,8 @@ async function loadSettings() {
   if (!settingsInitialized) {
     document.getElementById('checkBrokenUrlsBtn')?.addEventListener('click', checkBrokenUrls);
     document.getElementById('cleanupBrokenUrlsBtn')?.addEventListener('click', cleanupBrokenUrls);
+    document.getElementById('deduplicateBtn')?.addEventListener('click', deduplicateProducts);
+    document.getElementById('deduplicateEventsBtn')?.addEventListener('click', deduplicateEvents);
     settingsInitialized = true;
   }
 }
@@ -1309,3 +1316,37 @@ async function cleanupBrokenUrls() {
     resultEl.textContent = 'Failed to cleanup broken URLs';
   }
 }
+
+async function deduplicateProducts() {
+  if (!confirm('This will remove duplicate products. Continue?')) return;
+
+  const resultEl = document.getElementById('deduplicateResult');
+  resultEl.textContent = 'Removing duplicates...';
+
+  const result = await api('/products/deduplicate', { method: 'POST' });
+
+  if (result && result.success) {
+    let message = `Found ${result.duplicates_found} duplicate groups, removed ${result.products_removed} products.`;
+    if (Object.keys(result.by_site).length > 0) {
+      message += ' By site: ' + Object.entries(result.by_site).map(([site, count]) => `${site}: ${count}`).join(', ');
+    }
+    resultEl.textContent = message;
+  } else {
+    resultEl.textContent = 'Failed to deduplicate products';
+  }
+}
+
+async function deduplicateEvents() {
+  if (!confirm('This will remove duplicate events from the activity feed. Continue?')) return;
+
+  const resultEl = document.getElementById('deduplicateEventsResult');
+  resultEl.textContent = 'Cleaning up events...';
+
+  const result = await api('/events/deduplicate', { method: 'POST' });
+
+  if (result && result.success) {
+    resultEl.textContent = `Removed ${result.events_removed} duplicate events.`;
+  } else {
+    resultEl.textContent = 'Failed to clean up events';
+  }
+}