feat: FASE 0 - Setup progetto TieMeasureFlow

Struttura monorepo completa con server FastAPI e client Flask:
- Server: FastAPI + SQLAlchemy 2.0 async + Alembic migrations
- Client: Flask + blueprints (auth, measure, maker, statistics)
- Database: docker-compose MySQL 8.0 + Alembic async config
- Config: pydantic-settings, TailwindCSS, Flask-Babel i18n
- Piano implementazione completo (18 sezioni, 1600 righe)

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

server/database.py

@@ -0,0 +1,51 @@
+"""Async SQLAlchemy database engine and session management."""
+from collections.abc import AsyncGenerator
+
+from sqlalchemy.ext.asyncio import (
+    AsyncSession,
+    async_sessionmaker,
+    create_async_engine,
+)
+from sqlalchemy.orm import DeclarativeBase
+
+from config import settings
+
+# Create async engine
+engine = create_async_engine(
+    settings.database_url,
+    echo=False,
+    pool_size=10,
+    max_overflow=20,
+    pool_recycle=3600,
+)
+
+# Session factory
+async_session_factory = async_sessionmaker(
+    engine,
+    class_=AsyncSession,
+    expire_on_commit=False,
+)
+
+
+class Base(DeclarativeBase):
+    """Base class for all SQLAlchemy models."""
+    pass
+
+
+async def get_db() -> AsyncGenerator[AsyncSession, None]:
+    """Dependency for FastAPI - yields an async database session."""
+    async with async_session_factory() as session:
+        try:
+            yield session
+            await session.commit()
+        except Exception:
+            await session.rollback()
+            raise
+        finally:
+            await session.close()
+
+
+async def init_db() -> None:
+    """Create all tables (dev only - use Alembic in production)."""
+    async with engine.begin() as conn:
+        await conn.run_sync(Base.metadata.create_all)