Function test_erase_while_iterating

tests/misc/containers.cpp:911–942

// Erase while iterating for sequential containers (Pattern 1)
template<template<typename> class ContainerTemplate>
void test_erase_while_iterating() {
    using Container = ContainerTemplate<int>;
    Container c;
    // Insert multiple elements
    for (int i = 1; i <= 5; ++i) {
        c.push_back(i);
    }

    FL_CHECK(c.size() == 5);

    // Erase every other element while iterating
    int erased_count = 0;
    for (auto it = c.begin(); it != c.end(); ) {
        if (*it % 2 == 0) {
            it = c.erase(it);  // erase returns next iterator
            erased_count++;
        } else {
            ++it;
        }
    }

    FL_CHECK(erased_count == 2);  // Elements 2 and 4 were erased
    FL_CHECK(c.size() == 3);      // Elements 1, 3, 5 remain

    // Verify remaining elements
    int count = 0;
    for (auto it = c.begin(); it != c.end(); ++it) {
        count++;
        FL_CHECK(*it % 2 == 1);  // All remaining should be odd
    }
    FL_CHECK(count == 3);
}

// Erase while iterating for map containers (Pattern 2)
template<typename Map>