Full app rebuild: FastAPI backend + React Native mobile with auth, championships, admin

Backend (FastAPI + SQLAlchemy + SQLite):
- JWT auth with access/refresh tokens, bcrypt password hashing
- User model with member/organizer/admin roles, auto-approve members
- Championship, Registration, ParticipantList, Notification models
- Alembic async migrations, seed data with test users
- Registration endpoint returns tokens for members, pending for organizers
- /registrations/my returns championship title/date/location via eager loading
- Admin endpoints: list users, approve/reject organizers

Mobile (React Native + Expo + TypeScript):
- Zustand auth store, Axios client with token refresh interceptor
- Role-based registration (Member vs Organizer) with contextual form labels
- Tab navigation with Ionicons, safe area headers, admin tab for admin role
- Championships list with status badges, detail screen with registration progress
- My Registrations with championship title, progress bar, and tap-to-navigate
- Admin panel with pending/all filter, approve/reject with confirmation
- Profile screen with role badge, Ionicons info rows, sign out
- Password visibility toggle (Ionicons), keyboard flow hints (returnKeyType)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/app/crud/crud_participant.py

@@ -0,0 +1,34 @@
+import uuid
+from datetime import UTC, datetime
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.models.participant import ParticipantList
+
+
+async def get_for_championship(db: AsyncSession, championship_id: str | uuid.UUID) -> ParticipantList | None:
+    cid = championship_id if isinstance(championship_id, uuid.UUID) else uuid.UUID(str(championship_id))
+    result = await db.execute(select(ParticipantList).where(ParticipantList.championship_id == cid))
+    return result.scalar_one_or_none()
+
+
+async def create_or_get(db: AsyncSession, championship_id: uuid.UUID, published_by: uuid.UUID) -> ParticipantList:
+    existing = await get_for_championship(db, championship_id)
+    if existing:
+        return existing
+    pl = ParticipantList(championship_id=championship_id, published_by=published_by)
+    db.add(pl)
+    await db.commit()
+    await db.refresh(pl)
+    return pl
+
+
+async def publish(db: AsyncSession, pl: ParticipantList, notes: str | None = None) -> ParticipantList:
+    pl.is_published = True
+    pl.published_at = datetime.now(UTC)
+    if notes is not None:
+        pl.notes = notes
+    await db.commit()
+    await db.refresh(pl)
+    return pl