fix comment and tolerance in periapsis test

tests/test_periapsis_burn.cpp

@@ -65,8 +65,8 @@ SCENARIO("Periapsis-triggered prograde burn behavior", "[maneuver][periapsis]")
         // Pre-burn velocity captured at exact burn time (tight tolerance)
         REQUIRE_THAT(vec3_magnitude(br.velocity), WithinAbs(burn1_preburn_v, V_TOL));
 
-        // Semi-major axis after burn + 60s propagation (propagation-level tolerance)
-        REQUIRE_THAT(final_sma, WithinAbs(burn1_expected_sma, A_TOL * 10));
+        // Semi-major axis after burn
+        REQUIRE_THAT(final_sma, WithinAbs(burn1_expected_sma, A_TOL));
 
         INFO("Initial SMA: " << a_before << " m");
         INFO("Final SMA: " << final_sma << " m");