Fix TS errors: LRLS source filter type cast, remove unused overlapCount

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Stephan

src/components/LRLSExplorer.tsx

@@ -172,7 +172,7 @@ export default function LRLSExplorer() {
               </div>
               <select
                 value={sourceFilter}
-                onChange={e => setSourceFilter(e.target.value)}
+                onChange={e => setSourceFilter(e.target.value as SourceFilterValue)}
                 style={{
                   padding: '4px 10px',
                   background: '#1e2a45',

src/components/OverlapExplorer.tsx

@@ -67,7 +67,6 @@ export default function OverlapExplorer() {
   // Stats
   const totalRRLS = rrls.length;
   const totalNTS = nts.length;
-  const overlapCount = filtered.length;
   const rrlsOnly = totalRRLS - overlapChunks.size;
   const ntsOnly = totalNTS - overlapChunks.size;
   const overlapPct = totalRRLS > 0 ? ((overlapChunks.size / totalRRLS) * 100).toFixed(1) : '0';