cost service: add platform base + per-VIN resource model with CPU/RAM display

- Updated cost model to show: (Platform Base) + (Per-VIN × VINs)
- Platform base: 176 cores / 896GB RAM (Kafka, ClickHouse, MongoDB, Redis, PostgreSQL, gateway, monitoring)
- Per-VIN marginal: 50mc / 82MB per vehicle
- Added RESOURCE USAGE MODEL and COST FORMULA sections to report
- Added CPU (mc) and RAM (MB) columns to TOP COST VEHICLES table
- Updated README with new report output
- virtual-vehicle: documented Vault cert TTL error troubleshooting

deploy/cec-prd-cluster/cost.yaml

@@ -17,8 +17,8 @@ spec:
     spec:
       containers:
         - name: cost
-          image: fiskercloud.azurecr.io/cost:v7
-          imagePullPolicy: Always
+          image: fiskercloud.azurecr.io/cost:v11
+          imagePullPolicy: IfNotPresent
           ports:
             - containerPort: 8077
               name: http