fix(vendor): replace ASIN text input with MultiSelectDropdown for proper filtering

The free-text ASIN search was unclear and not working as expected.
Replace it with a proper MultiSelectDropdown (same as Market/Category
filters) — selecting an ASIN now strictly filters chart data to that
ASIN only.

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

components/VendorDataView.tsx

@@ -24,24 +24,27 @@ interface ChartPoint {
 const VendorDataView: React.FC<VendorDataViewProps> = ({ bsrData }) => {
   // Filters
   const [selectedMarkets, setSelectedMarkets] = useState<string[]>([]);
+  const [selectedAsins, setSelectedAsins] = useState<string[]>([]);
   const [selectedTopCats, setSelectedTopCats] = useState<string[]>([]);
   const [selectedDetailCats, setSelectedDetailCats] = useState<string[]>([]);
-  const [asinSearch, setAsinSearch] = useState('');
 
   // Extract available filter options from the dataset
-  const { availableMarkets, availableTopCats, availableDetailCats } = useMemo(() => {
+  const { availableMarkets, availableAsins, availableTopCats, availableDetailCats } = useMemo(() => {
     const markets = new Set<string>();
+    const asins = new Set<string>();
     const topCats = new Set<string>();
     const detailCats = new Set<string>();
 
     bsrData.forEach(r => {
       if (r.market) markets.add(r.market);
+      if (r.asin) asins.add(r.asin);
       if (r.topLevelName) topCats.add(r.topLevelName);
       if (r.detailLevelName) detailCats.add(r.detailLevelName);
     });
 
     return {
       availableMarkets: Array.from(markets).sort(),
+      availableAsins: Array.from(asins).sort(),
       availableTopCats: Array.from(topCats).sort(),
       availableDetailCats: Array.from(detailCats).sort()
     };
@@ -54,19 +57,18 @@ const VendorDataView: React.FC<VendorDataViewProps> = ({ bsrData }) => {
     if (selectedMarkets.length > 0) {
       result = result.filter(r => selectedMarkets.includes(r.market));
     }
+    if (selectedAsins.length > 0) {
+      result = result.filter(r => selectedAsins.includes(r.asin));
+    }
     if (selectedTopCats.length > 0) {
       result = result.filter(r => r.topLevelName && selectedTopCats.includes(r.topLevelName));
     }
     if (selectedDetailCats.length > 0) {
       result = result.filter(r => r.detailLevelName && selectedDetailCats.includes(r.detailLevelName));
     }
-    if (asinSearch.trim()) {
-      const terms = asinSearch.toLowerCase().split(',').map(t => t.trim()).filter(Boolean);
-      result = result.filter(r => terms.some(t => r.asin.toLowerCase().includes(t)));
-    }
 
     return result;
-  }, [bsrData, selectedMarkets, selectedTopCats, selectedDetailCats, asinSearch]);
+  }, [bsrData, selectedMarkets, selectedAsins, selectedTopCats, selectedDetailCats]);
 
   // Determine active markets in filtered data for series generation
   const activeMarkets = useMemo(() => {
@@ -172,6 +174,12 @@ const VendorDataView: React.FC<VendorDataViewProps> = ({ bsrData }) => {
           selected={selectedMarkets}
           onChange={setSelectedMarkets}
         />
+        <MultiSelectDropdown
+          label="ASIN"
+          options={availableAsins}
+          selected={selectedAsins}
+          onChange={setSelectedAsins}
+        />
         <MultiSelectDropdown
           label="Top Level Category"
           options={availableTopCats}
@@ -184,20 +192,13 @@ const VendorDataView: React.FC<VendorDataViewProps> = ({ bsrData }) => {
           selected={selectedDetailCats}
           onChange={setSelectedDetailCats}
         />
-        <input
+        {(selectedMarkets.length > 0 || selectedAsins.length > 0 || selectedTopCats.length > 0 || selectedDetailCats.length > 0) && (
-          type="text"
-          placeholder="Search ASINs (comma-separated)"
-          value={asinSearch}
-          onChange={e => setAsinSearch(e.target.value)}
-          className="bg-slate-900 border border-slate-700 rounded-lg px-3 py-2 text-sm text-slate-200 placeholder-slate-500 focus:outline-none focus:ring-1 focus:ring-indigo-500 w-64"
-        />
-        {(selectedMarkets.length > 0 || selectedTopCats.length > 0 || selectedDetailCats.length > 0 || asinSearch) && (
           <button
             onClick={() => {
               setSelectedMarkets([]);
+              setSelectedAsins([]);
               setSelectedTopCats([]);
               setSelectedDetailCats([]);
-              setAsinSearch('');
             }}
             className="text-xs text-slate-400 hover:text-white underline"
           >