Add user login feature

[devin-ai-integration]

Summary

Adds a user login feature to the Wordle app. Users can log in via a modal dialog accessible from the header, and their login state is persisted across sessions using localStorage.

Changes

• AuthContext (src/context/AuthContext.js): New React context providing user, login, and logout state, persisted to localStorage via the existing useLocalStorage hook.
• LoginModal (src/components/LoginModal/): Modal with username/password form, styled consistently with the existing app theme (dark mode, high contrast support).
• Header: Added login icon (person circle) for logged-out users, and username display + logout icon for logged-in users.
• App.jsx: Integrated the LoginModal state and passed it to the Header.
• index.js: Wrapped the app with AuthProvider.
• App.test.jsx: Fixed the test to wrap App with required context providers and test for actual content.

Screenshots

Login Modal:

Logged-in State (username in header):

Review & Testing Checklist for Human

• Verify login modal opens when clicking the person icon in the header
• Verify username displays in the header after logging in
• Verify logout button clears the user and shows the login icon again
• Verify login state persists after page refresh (localStorage)
• Verify the login modal works in both dark and light modes

Notes

• This is a client-side-only login (no backend authentication). Any username/password combination is accepted. This is suitable for a game app where login serves as a user identity feature rather than a security mechanism.
• The auth state is stored in localStorage under the key wordleUser.

Link to Devin session: https://app.devin.ai/sessions/93701e9af3af440a924d5eeccec4af34
Requested by: @shahmir-masood

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[devin-ai-integration]

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[devin-ai-integration]

End-to-End Test Results

Ran the app locally (npm start on localhost:3000) and tested the full login/logout flow via the browser UI.

All 5 tests passed.

Login Feature Tests

Test	Result
Login icon shown when logged out + empty form validation	Passed
Successful login shows username in header	Passed
Login state persists after page refresh	Passed
Logout clears state (persists after refresh)	Passed
Login modal renders correctly in light mode	Passed

Evidence Screenshots

Logged-out state (precondition):

Empty form validation — "Please enter a username":

Logged in — "testuser" in header:

Persists after refresh:

Logout clears state:

Light mode modal:

Devin session