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/harness/tools/bot/grab-bot-chat-tools.ts

@@ -74,7 +74,14 @@ export default async function grabBotChatTools({
 }: Params): Promise<HarnessTool[]> {
     const bot_id = bot.id || 0;
     const tools = [
-        ...grabBotTools({ user_id, bot_id, workspace_id, computers, session_id }),
+        ...(await grabBotTools({
+            user_id,
+            bot_id,
+            workspace_id,
+            computers,
+            session_id,
+            is_coordinator: bot.kind == "coordinator",
+        })),
         startTaskTool({
             user_id,
             bot_id,