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>

web/database.py

@@ -0,0 +1,24 @@
+from sqlalchemy import create_engine
+from sqlalchemy.orm import DeclarativeBase, sessionmaker
+
+from web.config import settings
+
+engine = create_engine(
+    settings.DATABASE_URL,
+    pool_pre_ping=True,
+    pool_recycle=3600,
+)
+
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+
+class Base(DeclarativeBase):
+    pass
+
+
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()