fix(docs): correct warm-toggle and Reconcile-without-Store claims

The failover chain editor leaves the warm toggle enabled on every row
(the model list has no backend field to gate on) and relies on the
server warning instead, so the docs describing it as disabled for
remote targets were wrong. Separately, syncstate's hydrate() returns
early with no Store or Loader, so a Reconcile tick is a no-op rather
than one that empties the map — correct that claim everywhere it was
repeated (contributor guide, distsync comment, design spec).

No behavior change.

Assisted-by: Claude:claude-opus-5-5
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

docs/content/features/model-failover.md

@@ -236,11 +236,11 @@ continue. On a single LocalAI instance, a restart removes the pin. In
 - The model editor's template picker has a **Failover Chain** template that
   starts a new model with two empty targets. Any model can also add a
   `failover.targets` field directly: each row picks a target model and a
-  **warm** toggle, with move up/down and remove controls. The warm toggle is
-  disabled, with an explanation, for a target on a remote (`localai-proxy` or
-  `cloud-proxy`) backend, since `warm` has no effect there. The field flags
-  fewer than two targets, a duplicate target, and the chain naming itself as
-  one of its own targets.
+  **warm** toggle, with move up/down and remove controls. The toggle is
+  available on every row; `warm` has no effect on a remote (`localai-proxy` or
+  `cloud-proxy`) target, and LocalAI logs a warning when it loads a chain with
+  one set. The field flags fewer than two targets, a duplicate target, and the
+  chain naming itself as one of its own targets.
 - Opening an existing chain in the model editor shows a health strip: the
   chain's status pill, its active target and how long it has been active,
   and a table of every target with its kind, warm flag, status, last probe