feat: add FastAPI backend with PostgreSQL and start script fixes

- Add server/ directory with FastAPI backend
- Fix server/start.sh to properly handle venv on Windows/Git Bash
- Add alembic migrations and pyproject.toml
- Add server tests

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

server/src/app/api/v1/endpoints/employees.py

@@ -0,0 +1,31 @@
+from __future__ import annotations
+
+from typing import Annotated
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+
+from app.api.deps import get_db
+from app.schemas.employee import EmployeeCreate, EmployeeRead
+from app.services.employee import EmployeeService
+
+router = APIRouter()
+DbSession = Annotated[Session, Depends(get_db)]
+
+
+@router.get("", response_model=list[EmployeeRead])
+def list_employees(db: DbSession) -> list[EmployeeRead]:
+    return EmployeeService(db).list_employees()
+
+
+@router.post("", response_model=EmployeeRead, status_code=status.HTTP_201_CREATED)
+def create_employee(payload: EmployeeCreate, db: DbSession) -> EmployeeRead:
+    return EmployeeService(db).create_employee(payload)
+
+
+@router.get("/{employee_id}", response_model=EmployeeRead)
+def get_employee(employee_id: str, db: DbSession) -> EmployeeRead:
+    employee = EmployeeService(db).get_employee(employee_id)
+    if employee is None:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Employee not found")
+    return employee