feat: add E2E tests for deeplink login flow

[decentraland-bot]

Summary

Add end-to-end Playwright tests for the new deeplink login feature that allows the Explorer desktop client to authenticate users via a browser-based wallet sign-in flow using decentraland:// deep links.

Background

The deeplink login flow is implemented across two PRs:

• Launcher: fix: improve deeplink passthrough handling and bridge cleanup launcher-rust#293 — forwards deeplink through bridge file in bridgeOnly mode
• Explorer: chore: authentication deep link login unity-explorer#9100 — DappDeepLinkAuthenticator creates a sign-in request, opens browser, awaits OS deep link, resolves identity

Flow under test

1. Explorer generates a client-side UUID (authRequestId)
2. Explorer opens browser to /auth/login/{authRequestId}?loginMethod=metamask&flow=deeplink
3. User connects wallet and signs in the browser
4. Auth dapp creates an identity on the auth server
5. Auth dapp redirects via decentraland://?signin={identityId}&authRequestId={authRequestId}
6. Explorer receives deep link, fetches identity from GET /identities/{identityId}

Test coverage

• New user deeplink login: wallet sign-in → quick-setup → identity creation → deep link redirect
• Recurrent user deeplink login: wallet sign-in → skip quick-setup → identity creation → deep link redirect
• Deep link redirect verification: authRequestId echoed correctly, signin identity ID present and fetchable

Files

• web/tests/auth/helpers/deeplink.ts — helpers for deeplink URL construction, redirect capture, identity fetching
• web/tests/auth/specs/deeplink-login.spec.ts — E2E specs

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Requested by Nicolas Lorusso via Slack