Add EvoSync v3 environment scaffold

FastAPI + Celery + Redis + MariaDB stack with 6-service docker-compose.
Includes project skeleton (config, database, models, tasks, migrations)
and health endpoint with passing test.

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

tests/conftest.py

@@ -0,0 +1,25 @@
+import pytest
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker
+
+from web.database import Base
+
+
+@pytest.fixture(scope="session")
+def engine():
+    eng = create_engine("sqlite:///:memory:", echo=False)
+    Base.metadata.create_all(eng)
+    yield eng
+    Base.metadata.drop_all(eng)
+
+
+@pytest.fixture
+def db_session(engine):
+    connection = engine.connect()
+    transaction = connection.begin()
+    Session = sessionmaker(bind=connection)
+    session = Session()
+    yield session
+    session.close()
+    transaction.rollback()
+    connection.close()

tests/test_health.py

@@ -0,0 +1,12 @@
+import pytest
+from httpx import ASGITransport, AsyncClient
+
+from web.main import app
+
+
+@pytest.mark.asyncio
+async def test_health_returns_ok():
+    async with AsyncClient(transport=ASGITransport(app=app), base_url="http://test") as client:
+        resp = await client.get("/health")
+    assert resp.status_code == 200
+    assert resp.json() == {"status": "ok"}