Add TypeBox Value.Equal deep-comparison as first optimization layer
in reconcileProps. When a fiber's cached node is deep-equal to the
next node, skip prepareUpdate, commitUpdate, and children
reconciliation entirely. New cachedNode field on Fiber stores the
last reconciled node for comparison.
Adds commitMutations function to reconcile.ts that processes fiber effects
in correct order: removes (reverse), inserts+moves (left-to-right with
insertBefore), updates (top-down). Integrates key-based reconciliation
pipeline into render() via reconcileNode, resolveUNode, and
createFiberForInsert.
First render still does a full mount and builds fiber tree. Subsequent
renders reconcile the new UNode tree against existing fibers: compare
props via prepareUpdate, apply changes via commitUpdate. Excess old
children remain (structural changes deferred to Phase 2). Function
components remain transparent during reconciliation.
