feat: EMEX HTTP decode + multi-candidate selection UI

Replace Playwright browser with pure HTTP for EMEX VIN decode:
- Vehicles.aspx, QuickGroups.aspx, QuickDetails.aspx all work
  without authentication — no session/browser needed
- VIN decode drops from ~10-20s (Playwright) to ~1-5s (HTTP)
- Playwright browser kept as fallback if HTTP fails

Add multi-candidate selection for EMEX (mirrors PartsCatalogs flow):
- EmexCandidate interface matches PcatCar shape so VehicleSelectModal
  renders without changes
- decodeVinOrCandidates(): single HTTP fetch returns vehicle OR
  candidates (avoids double Vehicles.aspx request)
- decodeVinByIndex(): resolves user-selected candidate by index
- vehicles.service: emexCandidates in VinResolveResult, emexCarIndex
  param in decodeVin/resolveVin, resolveEmexCarByIndex() method
- vehicles.controller: @Body("emexCarIndex") accepted
- search.tsx: candidateSource state, handleCandidateSelect sends
  emexCarIndex or pcatCarId based on source

Test VIN NM417800006410193 (Fiat SIENA) now shows 2-option modal.

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

apps/web/src/routes/dashboard/search.tsx

@@ -52,9 +52,10 @@ function SearchPage() {
   const [reportSending, setReportSending] = useState(false);
   const [reportSent, setReportSent] = useState(false);
 
-  // Vehicle candidate selection (PartsCatalogs multi-result)
+  // Vehicle candidate selection (PartsCatalogs or EMEX multi-result)
   const [candidates, setCandidates] = useState<any[] | null>(null);
   const [candidateVin, setCandidateVin] = useState("");
+  const [candidateSource, setCandidateSource] = useState<"parts-catalogs" | "emex" | null>(null);
   const [selectLoading, setSelectLoading] = useState(false);
 
   // Live preview state
@@ -149,13 +150,15 @@ function SearchPage() {
     try {
       const data = await api.post<any>("/vehicles/decode", { vin: cleanVin });
 
-      // Handle multiple vehicle candidates (PartsCatalogs)
+      // Handle multiple vehicle candidates (PartsCatalogs or EMEX)
       if (data.candidates && Array.isArray(data.candidates)) {
         setCandidates(data.candidates);
         setCandidateVin(cleanVin);
+        setCandidateSource(data.source ?? "parts-catalogs");
         capture("vin_decode_candidates", {
           vin: cleanVin,
           count: data.candidates.length,
+          source: data.source,
         });
         setLoading(false);
         return;
@@ -209,19 +212,24 @@ function SearchPage() {
     }
   }
 
-  async function handleCandidateSelect(pcatCarId: string) {
+  async function handleCandidateSelect(carId: string) {
     setSelectLoading(true);
     try {
-      const data = await api.post<any>("/vehicles/decode", {
-        vin: candidateVin,
-        pcatCarId,
-      });
+      const payload: Record<string, unknown> = { vin: candidateVin };
+      if (candidateSource === "emex") {
+        payload.emexCarIndex = parseInt(carId, 10);
+      } else {
+        payload.pcatCarId = carId;
+      }
+      const data = await api.post<any>("/vehicles/decode", payload);
       capture("vin_decode_candidate_selected", {
         vin: candidateVin,
-        pcatCarId,
+        source: candidateSource,
+        carId,
         vehicle_id: data.id,
       });
       setCandidates(null);
+      setCandidateSource(null);
       navigate({
         to: "/dashboard/vehicles/$id",
         params: { id: data.id },
@@ -233,6 +241,7 @@ function SearchPage() {
           : "Bir hata oluştu. Lütfen tekrar deneyin.";
       setError(message);
       setCandidates(null);
+      setCandidateSource(null);
       toast.error("Araç seçimi başarısız");
     } finally {
       setSelectLoading(false);
@@ -474,7 +483,7 @@ function SearchPage() {
         </div>
       )}
 
-      {/* ─── Vehicle Selection Modal (PartsCatalogs multi-result) ──── */}
+      {/* ─── Vehicle Selection Modal (PartsCatalogs / EMEX multi-result) ──── */}
       {candidates && (
         <VehicleSelectModal
           open={!!candidates}