feat: test version of unit swap tool.

backend/main.py

@@ -291,6 +291,14 @@ async def pending_deployments_page(request: Request):
     return templates.TemplateResponse("admin/pending_deployments.html", {"request": request})
 
 
+@app.get("/tools/unit-swap", response_class=HTMLResponse)
+async def unit_swap_page(request: Request):
+    """Mobile-first wizard for swapping a vibration unit (and optionally its
+    modem) at a monitoring location.  Pick project → location → incoming
+    unit → modem decision → confirm → optional photo of the new install."""
+    return templates.TemplateResponse("admin/unit_swap.html", {"request": request})
+
+
 @app.get("/modems", response_class=HTMLResponse)
 async def modems_page(request: Request):
     """Field modems management dashboard"""