React 19 useOptimistic for Instant UI Feedback: Building Confidence in AI Feature Interactions Without Optimistic Update Complexity

React 19 useOptimistic for Instant UI Feedback: Building Confidence in AI Feature Interactions Without Optimistic Update Complexity I've shipped nine AI features in CitizenApp, and I've watched users stare at loading spinners for 8–12 seconds while Claude processes their request. That's an eternity in SaaS. The old pattern—useState for optimistic state, useEffect for server calls, manual rollback on error—created brittle, hard-to-debug UIs that felt sluggish even when the backend was fast. Re...