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/pages/admin/bots/[bot_id]/(partials)/conversation-header-menu.tsx

@@ -11,6 +11,7 @@ import canManageCrew from "@/src/utils/rbac/can-manage-crew";
 import isPassThroughUser from "@/src/utils/rbac/is-pass-through-user";
 import BotComputersModal from "./bot-computers-modal";
 import BotFilesModal from "./bot-files-modal";
+import BotTasksModal from "./bot-tasks-modal";
 import BotModelsModal from "./bot-models-modal";
 import HeaderMenuItem from "./header-menu-item";
 import NewSessionButton from "./new-session-button";
@@ -101,6 +102,12 @@ export default function ConversationHeaderMenu({
                     workspace={workspace}
                     on_open={on_open}
                 />
+                <BotTasksModal
+                    menu
+                    bot={bot}
+                    workspace={workspace}
+                    on_open={on_open}
+                />
                 <BotComputersModal
                     menu
                     bot={bot}