fix(scheduling): use each candidate's own daysLeft for prediction

Different assessment targets have different end dates. Previously all
candidates used the current vehicle's daysLeft, causing wrong predictions.

Now each inventory vehicle computes its own daysLeft from its assessment
target's current_year_assessment_end_date. predictedAfterSwap uses the
candidate's own daysLeft instead of the current vehicle's.

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

src/server/routes/scheduling/suggestions.ts

@@ -250,12 +250,21 @@ app.get('/', async (c) => {
 
       // Cross-reference with assessment data
       const assessment = assessmentByPlate.get(plate);
+      // Compute this vehicle's own daysLeft from its assessment end date
+      let invDaysLeft = 0;
+      if (assessment?.current_year_assessment_end_date) {
+        const endDate = new Date(assessment.current_year_assessment_end_date);
+        invDaysLeft = Math.max(1, Math.ceil((endDate.getTime() - now.getTime()) / 86400000));
+      } else {
+        invDaysLeft = Math.max(1, Math.ceil((yearEnd.getTime() - now.getTime()) / 86400000));
+      }
       inventoryVehicles.push({
         plateNumber: plate,
         vehicleType,
         region,
         province,
         totalMileage: assessment ? Number(assessment.vehicle_total_mileage) || 0 : 0,
+        daysLeft: invDaysLeft,
         targetId: assessment ? (assessment.target_id as number) : null,
         targetName: assessment ? (targetMap.get(assessment.target_id)?.targetName ?? null) : null,
         yearTarget: assessment ? Number(assessment.current_year_mileage_task) || null : null,