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>

tests/unit/test_scheduler.py

@@ -0,0 +1,55 @@
+from datetime import datetime, timedelta, timezone
+
+import pytest
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine
+
+from app.config import settings
+from app.db.base import Base
+from app.db.models import Round
+from app.rounds.scheduler import RoundScheduler
+
+
+class FakeListener:
+    client = object()  # truthy sentinel; _tick only checks "is not None"
+    tip_height = 100
+    tip_header_hex = "00"
+
+
+@pytest.fixture
+async def session_factory():
+    engine = create_async_engine("sqlite+aiosqlite:///:memory:")
+    async with engine.begin() as conn:
+        await conn.run_sync(Base.metadata.create_all)
+    yield async_sessionmaker(engine, expire_on_commit=False)
+    await engine.dispose()
+
+
+async def test_tick_survives_sqlite_naive_datetime_roundtrip(session_factory, monkeypatch):
+    """Regression test: SQLite drops tzinfo on round-trip, so opened_at comes back
+    naive even though it was written as an aware UTC datetime. A prior bug compared
+    it directly against datetime.now(timezone.utc) and crashed with
+    "can't compare offset-naive and offset-aware datetimes" on every tick once a
+    round existed — this must not happen."""
+    monkeypatch.setattr(settings, "round_duration_seconds", 3600)  # not due yet
+    async with session_factory() as session:
+        session.add(Round(status="open", opened_at=datetime.now(timezone.utc)))
+        await session.commit()
+
+    scheduler = RoundScheduler(session_factory, FakeListener())
+    await scheduler._tick()  # must not raise
+
+
+async def test_tick_closes_round_with_no_participants_once_due(session_factory, monkeypatch):
+    monkeypatch.setattr(settings, "round_duration_seconds", 1)
+    past = datetime.now(timezone.utc) - timedelta(seconds=10)
+    async with session_factory() as session:
+        session.add(Round(status="open", opened_at=past))
+        await session.commit()
+
+    scheduler = RoundScheduler(session_factory, FakeListener())
+    await scheduler._tick()
+
+    async with session_factory() as session:
+        round_ = (await session.scalars(select(Round))).one()
+        assert round_.status == "closed"