Align sized cluster seeds and GET dumps with PVE wire shapes; restyle DATA panel.

- Scale small/large/big seeds (3×50 / 10×1000 / 20×2000) with proportional
  backups, snapshots, HA, replication, Ceph capacity, and OSD totals
  (10 / 100 / 500) plus matching node disks and crush/pg metadata
- Enrich handler responses for apt, certificates, qemu/lxc status, storage,
  SDN, metrics export, and related cluster/node dumps
- Flatten nested body_example fields into PARAMS and sync the request body
  via dotted paths (oVirt-style)
- Restyle DATA controls as size cards with full-width Reset to minimal /
  Refresh stats; unload reloads the minimal cluster

app/web/routes.py

@@ -161,7 +161,23 @@ async def ui_demo_state(request: Request) -> JSONResponse:
 @router.post("/ui/api/demo/load", include_in_schema=False)
 async def ui_demo_load(request: Request) -> JSONResponse:
     pool = _database_pool(request)
-    profile = build_profile("demo-cluster")
+    requested = "small"
+    if request.query_params.get("profile"):
+        requested = str(request.query_params.get("profile"))
+    else:
+        try:
+            body = await request.json()
+        except Exception:
+            body = None
+        if isinstance(body, dict) and body.get("profile"):
+            requested = str(body["profile"])
+    allowed = {"small", "large", "big"}
+    if requested not in allowed:
+        raise HTTPException(
+            status_code=400,
+            detail=f"unknown cluster profile '{requested}' (expected: small, large, big)",
+        )
+    profile = build_profile(requested)
     async with pool.acquire() as connection:
         await apply_seed(connection, profile)
         summary = await simulation_state_summary(connection)
@@ -179,7 +195,7 @@ async def ui_demo_unload(request: Request) -> JSONResponse:
             summary = await simulation_state_summary(connection)
     except Exception as error:
         raise HTTPException(
-            status_code=500, detail=f"failed to remove demo data: {error}"
+            status_code=500, detail=f"failed to reset to minimal cluster: {error}"
         ) from error
     return JSONResponse({"ok": True, "profile": profile.name, "summary": summary})