Build a Habit Tracker React App

PROJECT CONTEXT:
Build a beginner-friendly React habit tracker app that lets users add habits, mark them complete for the current day, view streaks and progress, edit or delete habits, and keep data saved between refreshes.

GOAL:
Create a real working React habit tracker app with usable state management, persistence, validation, and clear UI states rather than a static mockup.

REQUIREMENTS:
- Use React to build a single-page habit tracker app
- Allow users to create a new habit with at least a name field
- Display a list of all created habits
- Allow users to mark a habit as completed for today
- Prevent duplicate completions for the same habit on the same day
- Show current streak information for each habit
- Allow users to edit an existing habit
- Allow users to delete a habit
- Persist habit data in localStorage so it survives page refreshes
- Show empty states and validation messages for invalid form input

CONSTRAINTS:
- Keep the implementation beginner-friendly and contained in a simple React app
- Use localStorage for persistence instead of adding a backend
- Do not rely on fake data after initial implementation; all interactions must update real app state
- Keep the UI simple and functional rather than over-designing

DEFINITION OF DONE:
- A user can add a new habit and immediately see it in the habit list
- A user can mark a habit complete for today and the UI updates correctly without duplicate same-day entries
- Streak counts are computed from actual completion history and change when habits are completed on consecutive days
- A user can edit and delete habits and the list updates correctly
- Habit data persists after a full browser refresh via localStorage
- The app shows a useful empty state when no habits exist
- Invalid form submissions are blocked with visible validation feedback

COMMON FAILURES TO AVOID:
- Building a static UI that looks like a tracker but does not update real React state
- Marking habits complete visually without storing completion history per day
- Showing fake streak numbers instead of calculating them from recorded dates
- Forgetting localStorage sync so data disappears on refresh
- Allowing duplicate check-ins for the same habit on the same day
- Implementing edit buttons that do not actually save updated habit data