Add data quality normalization for cars: mileage in thousands and leasing prices

- detect km < 500 on non-new cars (e.g. '130' instead of '130.000')
- detect prices < 5.000 kr (likely monthly leasing rate not sale price)
- flags shown in AI prompt → forces low score (1-3)
- orange warning box in UI distinct from AI warnings

templates/index.html

@@ -425,6 +425,10 @@
         const pct   = Math.round(score * 10);
         const warn  = item.ai_warnings
           ? `<p class="text-xs mt-2" style="color:#dc2626">↑ ${item.ai_warnings}</p>` : "";
+        const qualityFlags = (item.data_quality_flags || []).length > 0
+          ? `<div class="mt-2 rounded-lg px-3 py-2" style="background:#fff7ed;border:1px solid #fed7aa">
+              ${item.data_quality_flags.map(f => `<p class="text-xs" style="color:#c2410c">${f}</p>`).join("")}
+             </div>` : "";
         const tag   = rankTag(score);
 
         const card = document.createElement("div");
@@ -447,6 +451,7 @@
               </div>
               <p class="text-xs leading-relaxed" style="color:#78716c">${item.ai_reason || ""}</p>
               ${warn}
+              ${qualityFlags}
             </div>
             <div class="shrink-0 text-right ml-2">
               <p class="font-semibold text-sm tabular-nums">${Number(item.price_dkk || 0).toLocaleString("da-DK")}<span class="text-xs font-normal ml-0.5" style="color:#a8a29e">kr</span></p>