Let the coordinator and workspace admins hand over tasks and routines

delegate_task takes a task_id to hand over a task already on a list: it
moves to the worker (a workspace's task stays on its list), goes to
doing, and the job is linked back so its end is noted on the task.
hand_over_schedule moves a bot's own routine to another bot, keeping its
workspace. Users get Hand over in the Tasks UI and both routine lists.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/utils/hand-over-place.test.ts

@@ -0,0 +1,21 @@
+import { describe, expect, test } from "bun:test";
+import handOverPlace from "./hand-over-place";
+
+describe("handOverPlace", () => {
+    test("work in a workspace stays there", () => {
+        expect(handOverPlace({ workspace_id: 3, label: "Task #1" })).toBe(3);
+        expect(handOverPlace({ workspace_id: 3, asked_workspace_id: 3, label: "Task #1" })).toBe(3);
+    });
+
+    test("refuses to move work out of its workspace", () => {
+        expect(() => handOverPlace({ workspace_id: 3, asked_workspace_id: 4, label: "Task #1" })).toThrow(
+            /Task #1 belongs to workspace 3/,
+        );
+    });
+
+    test("a bot's own goes to the asked workspace, else the new bot's own chat", () => {
+        expect(handOverPlace({ workspace_id: null, asked_workspace_id: 5, label: "Routine #2" })).toBe(5);
+        expect(handOverPlace({ workspace_id: null, label: "Routine #2" })).toBeNull();
+        expect(handOverPlace({ workspace_id: "", asked_workspace_id: null, label: "Routine #2" })).toBeNull();
+    });
+});

src/utils/hand-over-place.ts

@@ -0,0 +1,35 @@
+import AppError from "./app-error";
+
+type Params = {
+    /**
+     * The workspace the task's list or the routine belongs to now; none
+     * for a bot's own.
+     */
+    workspace_id?: number | string | null;
+    /**
+     * The workspace asked for, if any.
+     */
+    asked_workspace_id?: number | string | null;
+    /**
+     * What is handed over, for the refusal ("Task #4").
+     */
+    label: string;
+};
+
+/**
+ * Where handed-over work runs from now: a task on a workspace's list or a
+ * routine in a workspace stays in that workspace, and asking for another
+ * is refused; a bot's own goes to the asked workspace, or the new bot's
+ * own chat (null).
+ */
+export default function handOverPlace({ workspace_id, asked_workspace_id, label }: Params): number | null {
+    if (workspace_id) {
+        if (asked_workspace_id && Number(asked_workspace_id) != Number(workspace_id)) {
+            throw new AppError(`${label} belongs to workspace ${workspace_id}, and stays there. Leave workspace_id out.`);
+        }
+
+        return Number(workspace_id);
+    }
+
+    return asked_workspace_id ? Number(asked_workspace_id) : null;
+}