Add tasks: the crew's shared to-do list

Bots and workspaces each keep a list of work tracked until it's done, and
the bots move it along themselves as they work.

- tasks (one collection per bot or per workspace), task_notes (the
  progress log) and task_media (a deliverable or a reference file, its
  bytes a private media row served at /media/private/<id>)
- statuses todo/doing/blocked/done/cancelled, with blocked_reason while
  only the user can unblock it
- visibility as SQL in src/utils/task-access: a user's own bots and
  workspaces, a run's own list plus its workspaces, everything for the
  coordinator; every tool and endpoint resolves through it
- list_tasks, create_task and update_task on every run, so a chat reply,
  a task and a routine all read the list, log progress and file what they
  produced
- TasksNote on every run and TaskReminderNote in chat, so a greeting or a
  proposed next step brings pending work up in one measured line
- tasks group on the workspace dashboard and a tasks modal in the
  conversation header, sharing one form, row and detail panel
- a bot's or workspace's own chat uploads are read before the delete so
  none are stranded; bot files keep their folder

Also corrects the README's RAM guidance and table alignment.

src/functions/backend/db/tasks/find-duplicate-task.ts

@@ -0,0 +1,33 @@
+import type { BUN_SQLITE_COBBLE_TASKS } from "@/db/types/db";
+
+type Params = {
+    tasks: BUN_SQLITE_COBBLE_TASKS[];
+    title: string;
+    /**
+     * Same collection: a bot's own list, or a workspace's.
+     */
+    bot_id?: number | null;
+    workspace_id?: number | null;
+};
+
+/**
+ * A task in the same collection with the same title that's still open, so
+ * `ActionCheckNote` gets real behaviour: a bot updates the existing task
+ * instead of adding a second one for the same work.
+ */
+export default function findDuplicateTask({ tasks, title, bot_id, workspace_id }: Params) {
+    const wanted = title.trim().toLowerCase();
+
+    return (
+        tasks.find((task) => {
+            if (task.status == "done" || task.status == "cancelled") return false;
+            if (workspace_id) {
+                if (Number(task.workspace_id || 0) != Number(workspace_id)) return false;
+            } else if (Number(task.bot_id || 0) != Number(bot_id || 0)) {
+                return false;
+            }
+
+            return (task.title || "").trim().toLowerCase() == wanted;
+        }) || null
+    );
+}