大規模機能の実装

"Migrate from REST API to GraphQL across all frontend components"

"Switch from Stripe to a new billing provider across the entire payment system"

"Add comprehensive user roles and permissions system to the existing application"

Create a detailed implementation plan for migrating our entire authentication system
from Firebase Auth to Auth0. This affects user login, registration, session management,
role-based access control, and integrations across 50+ components.

Break this into major phases that can be implemented independently with clear
testing and validation points. Each phase should be completable in 1-2 days
and have minimal dependencies on other phases.

I'm implementing Phase 1 of the authentication migration plan documented in
IMPLEMENTATION_PLAN.md.

Phase 1 focuses on setting up Auth0 configuration and creating the basic
authentication service without affecting existing Firebase integration.

Please read the plan document and implement this phase, then update the
document to mark Phase 1 as complete.

Following IMPLEMENTATION_PLAN.md, implement Phase 3: Update all login components
to use the new Auth0 service while maintaining backward compatibility with
the existing Firebase auth as fallback.

Commit all changes for Phase 1 of the auth migration with a detailed message.

Create a commit for the Auth0 service setup work with bullet points for each major change.

Create a PR for the auth migration Phase 1 work on a new branch called auth-migration-phase-1.

Open a pull request with a comprehensive description of what was completed and testing done.

Run the authentication tests and verify the Auth0 service works in isolation.
Test user registration, login, and logout with the new service.

Test the migration script with a subset of test users. Verify data integrity
and that users can log in with both old and new systems.

Add a feature flag for auth0-migration with 10% rollout that can be controlled by environment variable.

Implement progressive rollout logic using feature flags to gradually migrate users from Firebase to Auth0.

Run the full test suite after each phase including unit, integration, and e2e tests.

Set up automated testing that validates auth migration functionality at each phase boundary.