feat: add validation for minimum length on various fields and update type definitions

backend/app/db/session.py

@@ -1,17 +1,38 @@
 from __future__ import annotations
 
 import logging
-from collections.abc import Generator
+from collections.abc import AsyncGenerator
 from pathlib import Path
 
-from sqlmodel import Session, SQLModel, create_engine
+import anyio
+from sqlalchemy.ext.asyncio import AsyncEngine, async_sessionmaker, create_async_engine
+from sqlmodel import SQLModel
+from sqlmodel.ext.asyncio.session import AsyncSession
 
 from alembic import command
 from alembic.config import Config
 from app import models  # noqa: F401
 from app.core.config import settings
 
-engine = create_engine(settings.database_url, pool_pre_ping=True)
+
+def _normalize_database_url(database_url: str) -> str:
+    if "://" not in database_url:
+        return database_url
+    scheme, rest = database_url.split("://", 1)
+    if scheme == "postgresql":
+        return f"postgresql+psycopg://{rest}"
+    return database_url
+
+
+async_engine: AsyncEngine = create_async_engine(
+    _normalize_database_url(settings.database_url),
+    pool_pre_ping=True,
+)
+async_session_maker = async_sessionmaker(
+    async_engine,
+    class_=AsyncSession,
+    expire_on_commit=False,
+)
 logger = logging.getLogger(__name__)
 
 
@@ -28,18 +49,19 @@ def run_migrations() -> None:
     logger.info("Database migrations complete.")
 
 
-def init_db() -> None:
+async def init_db() -> None:
     if settings.db_auto_migrate:
         versions_dir = Path(__file__).resolve().parents[2] / "alembic" / "versions"
         if any(versions_dir.glob("*.py")):
             logger.info("Running Alembic migrations on startup")
-            run_migrations()
+            await anyio.to_thread.run_sync(run_migrations)
             return
         logger.warning("No Alembic revisions found; falling back to create_all")
 
-    SQLModel.metadata.create_all(engine)
+    async with async_engine.begin() as conn:
+        await conn.run_sync(SQLModel.metadata.create_all)
 
 
-def get_session() -> Generator[Session, None, None]:
-    with Session(engine) as session:
+async def get_session() -> AsyncGenerator[AsyncSession, None]:
+    async with async_session_maker() as session:
         yield session