test(canvas): add pure-function tests for resolveRuntime and canvas-topology utilities
- preflight-resolveRuntime.test.ts: resolveRuntime from deploy-preflight.ts
covering explicit runtime-map entries, identity fallback, -default suffix
stripping, edge cases (empty string, multiple suffixes).
- canvas-topology-pure.test.ts: sortParentsBeforeChildren (topological
sort, orphan handling, no-op, non-mutating), defaultChildSlot (2-col
grid), childSlotInGrid (variable-size siblings, uniform-grid fallback),
parentMinSize (0–5 children, grid dimensions), parentMinSizeFromChildren
(variable sizes, empty array, width/height correctness).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>