Add non-wrapping grid option to vivarium

[Copilot]

• Fix GPU zero-padding bug in setup.ts: testNeighbor, testIdInPack, comparePointWithId, comparePointWithPoint, checkPointCount must use std.select to return element ID 0 (not ids[0]) when OOB in non-wrapping mode
• Fix JSDoc in vivarium.ts: "Defaults to true" → "Defaults to false"
• Fix docs vivarium.mdx: remove "fewer neighbors" language, describe zero-padding correctly
• Fix test "count at corner sees only in-bounds neighbors": fix comment (8 positions always, OOB are zero-padded to element 0)
• Redesign test "count at edge does not include out-of-bounds as neighbors": grid all-a with count(a, 8) is a bad proof because OOB also map to a; replace with a test that demonstrates OOB are element 0 not b
• Fix test "full board dies (overcrowding)": add { wrapping: true } — with correct zero-padding, 3x3 corner cells only see 3 alive in-bounds neighbours and survive
• Run tests

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