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/functions/backend/db/tasks/move-task.ts

@@ -0,0 +1,56 @@
+import BunSQLite from "@moduletrace/bun-sqlite";
+import type { BUN_SQLITE_COBBLE_TASKS } from "@/db/types/db";
+import AppError from "@/src/utils/app-error";
+import findDuplicateTask from "./find-duplicate-task";
+import grabTaskRow from "./grab-task-scope";
+import taskScopeValues from "./task-scope-values";
+
+type Params = {
+    task_id: number | string;
+    /**
+     * The collection it moves to: a bot's own list, or a workspace's.
+     */
+    bot_id?: number | string | null;
+    workspace_id?: number | string | null;
+};
+
+/**
+ * Moves a task to another collection, with its notes and files. Refused
+ * when the destination already has an open task with that title, so a
+ * hand-over never leaves two of the same. The caller checked who is
+ * asking reaches both. Returns the row as it is now.
+ */
+export default async function moveTask({ task_id, bot_id, workspace_id }: Params): Promise<BUN_SQLITE_COBBLE_TASKS> {
+    const task = await grabTaskRow({ task_id });
+    const place = taskScopeValues({ bot_id, workspace_id });
+
+    if (Number(task.bot_id || 0) == Number(place.bot_id || 0) && Number(task.workspace_id || 0) == Number(place.workspace_id || 0)) {
+        return task;
+    }
+
+    const there = (
+        await BunSQLite.sql<BUN_SQLITE_COBBLE_TASKS>({
+            sql: place.workspace_id
+                ? `SELECT * FROM tasks WHERE workspace_id = ? AND id != ?`
+                : `SELECT * FROM tasks WHERE bot_id = ? AND id != ?`,
+            values: [Number(place.workspace_id || place.bot_id), Number(task.id)],
+        })
+    ).payload || [];
+
+    const duplicate = findDuplicateTask({ tasks: there, title: task.title || "", ...place });
+
+    if (duplicate) {
+        throw new AppError(`That list already has task #${duplicate.id} "${duplicate.title}" open. Hand that one over instead.`);
+    }
+
+    const res = await BunSQLite.sql({
+        sql: `UPDATE tasks SET bot_id = ?, workspace_id = ?, updated_at = ? WHERE id = ?`,
+        values: [place.bot_id, place.workspace_id, Date.now(), Number(task.id)],
+    });
+
+    if (!res.success) {
+        throw new AppError(`Couldn't move the task: ${res.msg || res.error}`);
+    }
+
+    return await grabTaskRow({ task_id });
+}