Refactor backend to SQLModel; reset schema; add Company OS endpoints

backend/app/schemas/org.py

@@ -0,0 +1,31 @@
+from __future__ import annotations
+
+from sqlmodel import SQLModel
+
+
+class DepartmentCreate(SQLModel):
+    name: str
+    head_employee_id: int | None = None
+
+
+class DepartmentUpdate(SQLModel):
+    name: str | None = None
+    head_employee_id: int | None = None
+
+
+class EmployeeCreate(SQLModel):
+    name: str
+    employee_type: str
+    department_id: int | None = None
+    manager_id: int | None = None
+    title: str | None = None
+    status: str = "active"
+
+
+class EmployeeUpdate(SQLModel):
+    name: str | None = None
+    employee_type: str | None = None
+    department_id: int | None = None
+    manager_id: int | None = None
+    title: str | None = None
+    status: str | None = None