docs(forms): the public picker resolves its target from reference only

The `publicPicker.object` row described the tolerant chain this branch just
retired, so it now states the opposite of what the route does. Say what the
route does, and name the status an alias-spelled stored row now gets.

Claude-Session: https://claude.ai/code/session_01DapQyvYrFb1MxSYe7BL2nt
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

content/docs/ui/forms.mdx

@@ -257,7 +257,7 @@ sections: [{
 | `displayFields` | Fields projected into each result row (plus `id`); the visitor's `q` is `contains`-matched against the **first** entry. At most 5; omitted → `['name']`. |
 | `maxResults` | Rows per request, integer 1–50 (default 20). 50 is a hard server ceiling; there is **no pagination** on this surface (`offset` is pinned to 0), so a leaked endpoint cannot enumerate the table. |
 | `filter` | Static pre-filter rows (same `{ field, operator, value }` dialect as list-view filters), ANDed ahead of the visitor's search. |
-| `object` | The object to search. Optional — omit it and the server resolves the target from the field's own definition on the parent object (its `reference`, or a legacy `referenceTo` / `target` / `options.objectName` on a pre-fold stored row). Declare it only to search something other than what the field points at. |
+| `object` | The object to search. Optional — omit it and the server resolves the target from the field's own definition on the parent object: its `reference` key, and only that key. A stored row spelling the target `referenceTo` / `target` / `options.objectName` is **not** resolved — the route answers `500 LOOKUP_TARGET_MISSING` — because `FieldSchema` accepts no spelling but `reference`. Declare it only to search something other than what the field points at. |
 
 Those four keys are the whole block. It admits exactly what the route enforces
 — an unknown subkey, a 6th display field, or `maxResults: 51` is a **parse