test: Tighten eccentricity tolerances for parabolic boundary cases

- Near-parabolic (e=0.999) eccentricity tolerance: 1e-2 → 1e-3
- Highly hyperbolic (e=10.0) eccentricity tolerance: 1e-2 → 1e-3
- Validates improvements from PARABOLIC_TOLERANCE and near-parabolic handling
- All 82 tests passing (239,633 assertions)

tests/test_cartesian_to_elements_extreme.cpp

@@ -104,7 +104,7 @@ TEST_CASE("Cartesian to Elements - Edge Cases", "[orbital_mechanics]") {
 
         OrbitalElements recovered = cartesian_to_orbital_elements(position, velocity, M_sun);
 
-        REQUIRE_THAT(recovered.eccentricity, WithinAbs(0.999, 1e-2));
+        REQUIRE_THAT(recovered.eccentricity, WithinAbs(0.999, 1e-3));
         // Semi-major axis poorly conditioned for e≈1, skip test
     }
 
@@ -161,7 +161,7 @@ TEST_CASE("Cartesian to Elements - Edge Cases", "[orbital_mechanics]") {
 
         OrbitalElements recovered = cartesian_to_orbital_elements(position, velocity, M_sun);
 
-        REQUIRE_THAT(recovered.eccentricity, WithinAbs(10.0, 1e-2));
+        REQUIRE_THAT(recovered.eccentricity, WithinAbs(10.0, 1e-3));
         REQUIRE_THAT(recovered.semi_major_axis, WithinAbs(-1.0e10, 1e8));
     }