refactor(drafts): type UserDraftOverlay.other_drafts_users in the OpenAPI

The backend response carried other_drafts_users on every get-by-path
that supports the draft overlay, but the OpenAPI schema didn't declare
the field. Each route had to cast the typed response to `any` to read
it (and the sibling draft_saved_at), which obscured the real shape from
the type system and rotted the discoverability of the draft surface.

Add it to UserDraftOverlay. Frontend casts collapse to plain property
reads in the three editor routes.

backend/windmill-api/openapi.yaml

@@ -21049,6 +21049,25 @@ components:
         draft:
           type: object
           additionalProperties: true
+        other_drafts_users:
+          description: |
+            Other workspace users (and the legacy NULL-email row, if any)
+            with a saved draft at the same path. Populated only on the
+            authed user's "get by path" responses for kinds the editor
+            surfaces a fork banner for (script, flow, app, raw_app).
+            Empty / omitted for kinds without that UI.
+          type: array
+          items:
+            type: object
+            properties:
+              username:
+                type: string
+              email:
+                type: string
+              draft_saved_at:
+                type: string
+                format: date-time
+            required: [draft_saved_at]
       required: [is_draft]
     UserDraftItemKind:
       type: string

frontend/src/routes/(root)/(logged)/apps/edit/[...path]/+page.svelte

@@ -100,11 +100,11 @@
 			getDraft
 		})
 		if (tok !== loadAppToken) return
-		otherDraftsUsers = ((backendApp as any).other_drafts_users ?? []) as OtherDraftUser[]
+		otherDraftsUsers = (backendApp.other_drafts_users ?? []) as OtherDraftUser[]
 		if ($workspaceStore && path) {
 			UserDraftDbSyncer.recordRemoteSync(
 				{ workspace: $workspaceStore, itemKind: 'app', path },
-				(backendApp as any).draft_saved_at as string | undefined
+				backendApp.draft_saved_at
 			)
 		}
 		// Apply the user's saved draft to `.value`. The autosave for apps

frontend/src/routes/(root)/(logged)/flows/edit/[...path]/+page.svelte

@@ -203,11 +203,11 @@
 			getDraft
 		})
 		if (tok !== loadFlowToken) return
-		otherDraftsUsers = ((backendFlow as any).other_drafts_users ?? []) as OtherDraftUser[]
+		otherDraftsUsers = (backendFlow.other_drafts_users ?? []) as OtherDraftUser[]
 		if ($workspaceStore && flowDraftPath) {
 			UserDraftDbSyncer.recordRemoteSync(
 				{ workspace: $workspaceStore, itemKind: 'flow', path: flowDraftPath },
-				(backendFlow as any).draft_saved_at as string | undefined
+				backendFlow.draft_saved_at
 			)
 		}
 		// Re-evaluate the "new flow" signal on each load — flips to

frontend/src/routes/(root)/(logged)/scripts/edit/[...path]/+page.svelte

@@ -148,7 +148,7 @@
 				getDraft
 			})
 			if (tok !== loadScriptToken) return
-			otherDraftsUsers = ((backendScript as any).other_drafts_users ?? []) as OtherDraftUser[]
+			otherDraftsUsers = (backendScript.other_drafts_users ?? []) as OtherDraftUser[]
 			// Seed the per-tab `last_sync` map with the server's draft
 			// timestamp so the next autosave attaches a matching
 			// `last_sync` and the backend can reject stale writes.
@@ -157,7 +157,7 @@
 			if ($workspaceStore && page.params.path) {
 				UserDraftDbSyncer.recordRemoteSync(
 					{ workspace: $workspaceStore, itemKind: 'script', path: page.params.path },
-					(backendScript as any).draft_saved_at as string | undefined
+					backendScript.draft_saved_at
 				)
 			}
 			if (backendScript.is_draft) {