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

backend/app/api/utils.py

@@ -0,0 +1,28 @@
+from __future__ import annotations
+
+import json
+from typing import Any
+
+from sqlmodel import Session
+
+from app.models.activity import Activity
+
+
+def log_activity(
+    session: Session,
+    *,
+    actor_employee_id: int | None,
+    entity_type: str,
+    entity_id: int | None,
+    verb: str,
+    payload: dict[str, Any] | None = None,
+) -> None:
+    session.add(
+        Activity(
+            actor_employee_id=actor_employee_id,
+            entity_type=entity_type,
+            entity_id=entity_id,
+            verb=verb,
+            payload_json=json.dumps(payload) if payload is not None else None,
+        )
+    )