chore: changeset for the flow-inspector sibling-block fix (objectstack#4045)

Author: claude

.changeset/flow-inspector-sibling-block-preservation.md

@@ -0,0 +1,42 @@
+---
+"@object-ui/app-shell": patch
+---
+
+fix(flow-designer): a published `configSchema` can no longer delete a node's sibling-block editors — objectstack#4045
+
+`FlowNodeInspector` resolved its form as `serverFields ?? fieldsForNodeType(type)`,
+so an engine-published `configSchema` **replaced the hand-written field group
+wholesale**. But a `configSchema` describes `node.config` and nothing else
+(ADR-0018), and `jsonSchemaToFlowFields` roots every field it emits at
+`['config', key]` — so the replacement silently deleted every editor rooted
+anywhere else.
+
+18 fields sit in that blast radius: `connectorConfig.*` (3), `waitEventConfig.*`
+(5), `boundaryConfig.*` (6) and the top-level `timeoutMs` (4). For `wait` and
+`boundary_event` those blocks are the node's **entire** contract.
+
+This already happened once. `connector_action`'s descriptor published a schema
+declaring `connectorId` / `actionId` / `input` as CONFIG keys, so against a live
+backend the generated form replaced the `connectorConfig` group — connector and
+action pickers included — and an author configuring a connector node in Studio
+wrote the trio to `node.config`, which the executor never reads. The node then
+refused to dispatch with `connectorConfig.connectorId and .actionId are
+required`. objectstack#4210 retired that schema on the server; this change is
+what stops the next mis-rooted one from doing the same to `wait` or
+`boundary_event`.
+
+New `mergeServerFlowFields()` splits the resolution by root:
+
+- **the server owns the config-rooted fields** — it is the authority on what the
+  executor actually reads, so its set replaces the hand-written config fields
+  rather than merging with them (a stale client key must not linger);
+- **non-config fields are always preserved** from the hand-written group, in
+  declared order;
+- a server field duplicating a preserved sibling key is **dropped**, not rendered
+  twice — two editors for one value, one of them writing where nothing reads, is
+  the same bug wearing a different hat.
+
+With no published schema the hand-written group is still used whole, unchanged.
+
+Verified by mutation: reverting to the old replacement turns all three new
+assertions red, one of which replays the `connector_action` incident directly.