Tell every bot its own id, in every run

The bot's id never reached its prompt: `composeBotPrompt` only took its
instructions, the appendix, its memory and its workspace, and
`grabBotPrompt` never passed `bot.id` or `bot.name` on. A bot could only
learn its id by accident, from a tool description that named it, so
"which bot am I" was unanswerable in most contexts.

- Open the prompt with who the bot is (`composeIdentity`): its name,
  whether it's the coordinator or a worker, its role, and its id, said
  to be how tools and refs point back at it. `grabBotPrompt` now passes
  the bot, which covers chat replies, tasks, routines and delegated
  tasks, since both runners build their prompt there.
- Turn the notes' example refs into functions bound to the running bot:
  `chatReplyNote`, `botFilesNote` and `coordinatorReplyNote` take its id,
  so the folder-ref example no longer points at a hardcoded `owner_id: 5`
  (another bot's folder) nor `[bot:3]`. ComputerFilesNote keeps the
  computer it's given.
- Stop `create_task` from hiding the worker's own id in its own chat.

Tests: four new `composeBotPrompt` cases pin the identity block (worker,
coordinator, unnamed, no bot at all), and a new `harness-prompts.test.ts`
checks each note's own-folder and self refs point at exactly the running
bot, for three ids.

src/harness/tools/bot/tasks/create-task-tool.ts

@@ -101,7 +101,7 @@ export default function createTaskTool({
         name: "create_task",
         description: is_coordinator
             ? `Add a task to a list: a worker's own (${crew || "no workers yet"}), a workspace's shared one (${places || "no workspaces yet"}), or your own (leave both ids out). Write the description as a brief: what to do, where, and how you'll know it's done. A workspace's tasks are visible to every bot working there.`
-            : `Add a task to a list: ${workspace_id ? "this workspace's shared one (leave the ids out), or your own (bot_id: " + bot_id + ")" : "your own (leave the ids out)"}. Write the description as a brief: what to do, where, and how you'll know it's done.`,
+            : `Add a task to a list: ${workspace_id ? `this workspace's shared one (leave the ids out), or your own (bot_id: ${bot_id})` : `your own, bot_id ${bot_id} (or leave the id out, since it defaults to yours)`}. Write the description as a brief: what to do, where, and how you'll know it's done.`,
         schema: z.object({
             title: z.string().trim().min(1).max(AppData.TaskTitleMaxLength).describe(`A short label`),
             description: z
@@ -111,7 +111,7 @@ export default function createTaskTool({
             bot_id: z.number().int().optional().describe(
                 is_coordinator
                     ? `Whose own list, when it isn't a workspace's. Leave out for your own.`
-                    : `Your own id (${bot_id}), to keep it in your list rather than the workspace's.`,
+                    : `Your own id (${bot_id}), to keep it in your list rather than the workspace's; leaving it out has the same effect here.`,
             ),
             workspace_id: z
                 .number()