E2E Snapshot Tests

• Run the full suite with SPACE_DISABLE_AUDIO=1 SPACE_ASSETS_PATH=$(pwd)/assets make test-e2e.
• Update goldens with SPACE_SNAPSHOT_UPDATE=name1,name2 SPACE_DISABLE_AUDIO=1 SPACE_ASSETS_PATH=$(pwd)/assets make test-e2e.
• Individual tests can be run via ./build/space -m tests.e2e.<module>:main (e.g. tests.e2e.test-image:main).
• Snapshot images live in assets/lua/tests/data/snapshots/ and should be inspected directly when adding/debugging tests.