fixes and refactor

static/js/highlight.js

@@ -2,13 +2,23 @@
   function buildTokens(rawQuery) {
     const q = (rawQuery || '').trim();
     if (!q) return [];
-    // Normalize punctuation to spaces, trim non-alphanumerics at ends, dedupe
+    // Normalize punctuation to spaces, trim non-alphanumerics at ends
     const tokens = q
       .replace(/[,_;:]+/g, ' ')
       .split(/\s+/)
       .map(t => t.replace(/^[^A-Za-z0-9]+|[^A-Za-z0-9]+$/g, ''))
       .filter(Boolean);
-    return Array.from(new Set(tokens));
+    // Case-insensitive dedupe while preserving original order and casing (parity with server)
+    const seen = new Set();
+    const result = [];
+    for (const tok of tokens) {
+      const lowered = tok.toLowerCase();
+      if (!seen.has(lowered)) {
+        seen.add(lowered);
+        result.push(tok);
+      }
+    }
+    return result;
   }
 
   function escapeHtml(text) {