Fix missing negEnd0 radius comparison in ContCapsule3 MergeContainers

[CodeReclaimers]

In MergeContainers, the negEnd0 distance+radius is computed (line 171) but never compared against the running radius maximum before being overwritten by the posEnd1 computation (line 174). If negEnd0 is the farthest endpoint from the merge axis, the merged capsule is too narrow.

Fix: add the missing if (tmp > radius) { radius = tmp; } block, matching the pattern used for the other three endpoints.

Test (CMakeLists.txt)

cmake_minimum_required(VERSION 3.14)
project(test_issue_5_1 LANGUAGES CXX)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(GTE_ROOT "${CMAKE_CURRENT_SOURCE_DIR}/../../GTE")
add_executable(test_issue_5_1 test_issue_5_1.cpp)
target_include_directories(test_issue_5_1 PRIVATE "${GTE_ROOT}")

Test (test_issue_5_1.cpp)

#include <cmath>
#include <cstdlib>
#include <iostream>
#include <Mathematics/ContCapsule3.h>

static bool test_asymmetric_capsules()
{
    using Real = double;
    using Vec3 = gte::Vector3<Real>;

    // Capsule0: long segment from (-10,-8,0) to (2,0,0), radius 2.
    gte::Segment3<Real> seg0(Vec3{-10.0,-8.0,0.0}, Vec3{2.0,0.0,0.0});
    gte::Capsule3<Real> capsule0(seg0, 2.0);

    // Capsule1: short segment near origin, radius 1.
    gte::Segment3<Real> seg1(Vec3{-1.0,0.0,0.0}, Vec3{1.0,0.0,0.0});
    gte::Capsule3<Real> capsule1(seg1, 1.0);

    gte::Capsule3<Real> merge;
    gte::MergeContainers(capsule0, capsule1, merge);

    // Merged capsule must contain capsule0's negative end sphere.
    gte::Sphere3<Real> negEnd0Sphere(seg0.p[0], capsule0.radius);
    return gte::InContainer<Real>(negEnd0Sphere, merge);
}

int main()
{
    return test_asymmetric_capsules() ? EXIT_SUCCESS : EXIT_FAILURE;
}