[justavibedev]

Resuming a two-island checkpoint with database.num_islands: 4 reconstructs four island populations but restores only two MAP-Elites feature maps. The first add(..., target_island=2) raises IndexError when it accesses the missing map.

Extend the loaded map list with independent empty dictionaries for the reconstructed islands. This preserves saved cells and the existing behavior of retaining saved islands when the configured count is smaller.

Regression coverage exercises adding to both new islands, independent maps, preserved saved maps, unchanged and reduced configured counts, metadata without saved feature maps, and another save/load cycle. Two regression cases fail with IndexError on the base commit and pass with this change.

Validation:

• Python 3.10.21: OPENAI_API_KEY=test-key-for-unit-tests python -m unittest discover -s tests -p 'test_*.py' -v — 794 tests, OK, with two existing scipy-dependent tests skipped because scipy is not installed.
• Python 3.12.11: 64 focused database, island, checkpoint, and feature-stat tests passed.
• Black on both changed files, isort on the new test module, and git diff --check passed.

No live-model integration tests were run locally. Codex assisted with development and testing.