Retire a shared node in use with ?detach=true

DELETE /flows/library/{name} still answers 409 while nodes use the source.
With detach=true each of them keeps a copy of the code, in the published
flow and the draft, the source is deleted and the running users rebuild.

frontend/src/client/sdk.gen.ts

@@ -819,8 +819,12 @@ export class FlowsService {
     /**
      * Delete Shared Node
      * Remove a shared source, as long as no flow still runs it.
+     *
+     * With ``detach``, every node using it keeps a copy of the code as its own
+     * first, so the source can be retired while flows still use it.
      * @param data The data for the request.
      * @param data.libName
+     * @param data.detach
      * @returns Message Successful Response
      * @throws ApiError
      */
@@ -831,6 +835,9 @@ export class FlowsService {
             path: {
                 lib_name: data.libName
             },
+            query: {
+                detach: data.detach
+            },
             errors: {
                 422: 'Validation Error'
             }

frontend/src/client/types.gen.ts

@@ -1716,6 +1716,7 @@ export type FlowsReadGraphResponse = (BrainGraph);
 export type FlowsReadLibraryResponse = (Array<LibraryNode>);
 
 export type FlowsDeleteSharedNodeData = {
+    detach?: boolean;
     libName: string;
 };