feat: add Alembic database migrations

Replace create_all() startup approach with Alembic for proper schema
versioning. Includes initial migration for users and evotor_connections
tables, entrypoint script that runs migrations before starting uvicorn.

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

web/main.py

@@ -3,8 +3,6 @@ from fastapi.staticfiles import StaticFiles
 from starlette.middleware.sessions import SessionMiddleware
 
 from web.config import settings
-from web.database import engine, Base
-from web.models import User, EvotorConnection  # noqa: F401 — registers models with Base
 from web.routes import auth, profile, reset, evotor
 
 app = FastAPI(title="EvoSync — Личный кабинет")
@@ -16,8 +14,3 @@ app.include_router(auth.router)
 app.include_router(profile.router)
 app.include_router(reset.router)
 app.include_router(evotor.router)
-
-
-@app.on_event("startup")
-def on_startup():
-    Base.metadata.create_all(bind=engine)