feat: implement Car inheritance

src/main/java/org/example/model/Car.java

@@ -0,0 +1,40 @@
+package org.example.model;
+
+/*
+ * Car extends Vehicle.
+ * This class SHOULD implement Serviceable.
+ *
+ * Service logic for Car:
+ * - needsService(): return true if mileage > 10,000
+ * - performService(): print "General car service completed"
+ */
+
+import org.example.behavior.Serviceable;
+
+public class Car extends Vehicle implements Serviceable {
+
+    private int seats;
+
+    public Car(String brand, String model, int year,
+               double mileage, int seats) {
+
+        // TODO: Call super constructor
+        this.seats = seats;
+    }
+
+    // TODO: Override getEnergyType() → return "Unknown"
+
+    // TODO: Implement showDetails()
+
+    /*
+     * Implement Serviceable methods:
+     *
+     * needsService(Vehicle v):
+     * - Check the mileage of the current car
+     * - If mileage > 10000 return true
+     * - Otherwise return false
+     *
+     * performService():
+     * - Print: "General car service completed"
+     */
+}