feat(api): identify-but-no-catalog fallback instead of a bare "unsupported"

When no catalog source can decode a VIN, the decode dead-ended with "Şase
numarası tanınamadı. Marka desteklenmiyor." even for valid, recognizable cars.
Now, before that error, run a best-effort identification (offline Corgi WMI +
NHTSA); if it yields a brand/model/year, tell the dealer what the car is and that
the request was logged ("Bu araç X olarak tanındı, ancak ... katalog henüz yok.
Talebiniz kaydedildi."). Logged distinctly (identified_no_catalog) so the coverage
backlog can be mined. Skipped on budget-abort.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/api/src/vehicles/vehicles.service.ts

@@ -121,8 +121,32 @@ export class VehiclesService {
     const resolved = await this.resolveVin(vin, pcatCarId, emexCarIndex, userId, ctx);
 
     if (!resolved) {
-      const finalSource = ctx.timings.aborted ? "aborted" : "none";
+      const aborted = !!ctx.timings.aborted;
-      const errMsg = ctx.timings.aborted
+      // No catalog source has this VIN. Best-effort identification (offline Corgi
+      // WMI + NHTSA) so we don't dead-end with a bare "unsupported" — at least tell
+      // the dealer what car it is. The miss is logged (with wmi) for the coverage
+      // backlog either way. Skip on budget-abort (already a timeout, don't pile on).
+      if (!aborted) {
+        const basic = await this.identifyBasic(vin);
+        if (basic) {
+          ctx.timings.identified_no_catalog = 1;
+          await this.logQuery(
+            userId,
+            vin,
+            null,
+            "none",
+            false,
+            Date.now() - startTime,
+            `No catalog — identified as ${basic}`,
+            ctx.timings,
+          );
+          throw new BadRequestException(
+            `Bu araç ${basic} olarak tanındı, ancak bu şase için parça kataloğu henüz mevcut değil. Talebiniz kaydedildi.`,
+          );
+        }
+      }
+      const finalSource = aborted ? "aborted" : "none";
+      const errMsg = aborted
         ? `Decode budget exceeded (${VehiclesService.RESOLVE_BUDGET_MS}ms)`
         : "Unknown VIN/brand";
       await this.logQuery(
@@ -500,6 +524,31 @@ export class VehiclesService {
     return "timeout";
   }
 
+  /**
+   * Best-effort identification for VINs no catalog could decode: offline Corgi WMI
+   * → brand, NHTSA → model/year. Returns a display string ("Renault Clio 2018") or
+   * null if even the brand is unknown. Only used to give the user a meaningful
+   * "identified but no catalog yet" message instead of a bare "unsupported".
+   */
+  private async identifyBasic(vin: string): Promise<string | null> {
+    const corgi = this.corgiService.decodeVin(vin);
+    let brand: string | null = corgi?.isKnown ? corgi.brandName : null;
+    let model: string | null = null;
+    let year: string | number | null = corgi?.modelYear ?? null;
+    try {
+      const nhtsa = await this.vinApiService.decodeVin(vin);
+      if (nhtsa) {
+        brand = brand || nhtsa.make || null;
+        model = nhtsa.model || null;
+        year = year || nhtsa.modelYear || null;
+      }
+    } catch {
+      // NHTSA is best-effort; a brand from Corgi alone is still useful.
+    }
+    if (!brand && !model) return null;
+    return [brand, model, year].filter(Boolean).join(" ").trim() || null;
+  }
+
   /** Actual decode chain — does NOT touch the cache or lock. */
   private async doResolveVin(
     vin: string,