Add parameterized ShapeContractTest for Shape interface invariants

Verify clone(), getBounds(), and translate() contracts across all Shape
implementations (SRectangle, SCircle, STriangle, SText, SCollection)
using @ParameterizedTest + @MethodSource.

Also adds junit-jupiter-params dependency to pom.xml.

Closes #8

pom.xml

@@ -58,5 +58,12 @@
             <version>5.10.0</version>
             <scope>test</scope>
         </dependency>
+
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-params</artifactId>
+            <version>5.10.0</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 </project>