Added automated science tests to ExoSim.The new test suite verifies the circle-overlap formula used for grazing transits, including exact analytical values, containment, separation, symmetry, and boundary conditions. It also tests full, grazing, and missed transit visibility, confirms that the signal decreases as projected separation increases, and checks the geometry-classification thresholds. All 17 tests pass, and ExoSim still completes a clean production build with no TypeScript or compilation errors.