Implement full MVP: auth, HD wallet, Electrum client, deposits, bets, round/draw engine, payout, withdrawals, RBF, admin+audit

All 10 build-order stages complete and unit-tested (49 tests). Verified live on
mainnet: registration/address derivation, deposit crediting, a real 10 PLM bet
(broadcast + confirmed + change credited). A full round close->draw->payout
cycle was triggered live and was in progress at commit time. Withdrawal and RBF
bump are unit-tested but not yet exercised against a live broadcast. Known gaps
(scheduler doesn't resume mid-flight rounds after restart, payout has no retry,
no deployment setup, etc.) are documented in CLAUDE.md.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/auth/routes.py

@@ -0,0 +1,70 @@
+from fastapi import APIRouter, Depends, HTTPException, Request, status
+from pydantic import BaseModel
+from sqlalchemy import func, select
+from sqlalchemy.exc import IntegrityError
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.auth.security import create_access_token, hash_password, verify_password
+from app.db.models import User
+from app.db.session import get_session
+from app.wallet.hd import derive_user_address
+
+router = APIRouter(prefix="/auth", tags=["auth"])
+
+_MAX_REGISTER_RETRIES = 5
+
+
+class RegisterRequest(BaseModel):
+    username: str
+    password: str
+
+
+class TokenResponse(BaseModel):
+    access_token: str
+    address: str
+
+
+@router.post("/register", response_model=TokenResponse, status_code=status.HTTP_201_CREATED)
+async def register(
+    body: RegisterRequest, request: Request, session: AsyncSession = Depends(get_session)
+) -> TokenResponse:
+    existing = await session.scalar(select(User).where(User.username == body.username))
+    if existing is not None:
+        raise HTTPException(status.HTTP_409_CONFLICT, "username already taken")
+
+    password_hash = hash_password(body.password)
+
+    for _ in range(_MAX_REGISTER_RETRIES):
+        max_index = await session.scalar(select(func.max(User.derivation_index)))
+        next_index = 0 if max_index is None else max_index + 1
+        address = derive_user_address(next_index)
+        user = User(
+            username=body.username,
+            password_hash=password_hash,
+            derivation_index=next_index,
+            address=address,
+        )
+        session.add(user)
+        try:
+            await session.commit()
+        except IntegrityError:
+            await session.rollback()
+            continue
+        await session.refresh(user)
+        request.app.state.electrum_listener.address_for_new_user(user.id, user.address)
+        return TokenResponse(access_token=create_access_token(user.id), address=user.address)
+
+    raise HTTPException(status.HTTP_409_CONFLICT, "could not allocate a derivation index, retry")
+
+
+class LoginRequest(BaseModel):
+    username: str
+    password: str
+
+
+@router.post("/login", response_model=TokenResponse)
+async def login(body: LoginRequest, session: AsyncSession = Depends(get_session)) -> TokenResponse:
+    user = await session.scalar(select(User).where(User.username == body.username))
+    if user is None or not verify_password(body.password, user.password_hash):
+        raise HTTPException(status.HTTP_401_UNAUTHORIZED, "invalid credentials")
+    return TokenResponse(access_token=create_access_token(user.id), address=user.address)