Let the coordinator create bots and put them in workspaces

The coordinator had no tool to add a worker, so a request to create one
fell back to update_workspace and wrote a bot that did not exist into the
workspace context. create_bot now adds a worker with its name, role and
instructions and joins it to a workspace, and add_bot_to_workspace puts an
existing worker in one. Both are coordinator-only and chat-replies-only,
and createBot still enforces the crew-manager check.

The coordinator's prompts now say how a bot gets created, and that one
which does not exist is never written into workspace context.

pick-free-hue moves to utils so the tool can pick a hue without importing
from layouts.

AGENTS.md

@@ -130,7 +130,7 @@ Envs are set in Settings, under Environment (super admin only), not in `.env`. T
 - **Automatic picks** (`rank-auto-models`): free models that can do the job (on the setting's provider when it has one; a provider without free models needs a picked model) (`model-serves-harness`: text needs tools), by vendor `AutoModelVendorPreference` (DeepSeek, Qwen, NVIDIA, Liquid), then other vendors that look competent (`AppData.HarnessAutoMin*`), then routers; within a vendor by intelligence index, then full-size before small, newest first. Transcription puts real speech-to-text models first.
 - **Calling:** `resolveHarnessCandidates` (pinned, then automatic) -> `withCandidates` tries them in order with process-wide cooldowns (`resolve/harness-cooldowns.ts`): rate limits and outages rest the model (until `Retry-After` when given), 401/402 rest the whole provider, 403/404 rest the model for an hour. Errors are `HarnessError` (`code` provider|unavailable|aborted, `retryable`), classified in `to-harness-error.ts`. Entry points: `text/generate-text.ts` (one turn), `text/run-text-loop.ts` (tool loop, sticks to one model, wraps up after `HarnessMaxToolSteps`, trims the oldest tool output before each turn to fit the model's context, `fit-transcript-to-context.ts`), `media/read-image.ts`, `media/read-media.ts` (documents locally via `fileToText`, images and audio through their harnesses), `audio/transcribe-audio.ts`, `audio/speak-text.ts`, `image/generate-image.ts`. A text model that can't take an image or audio part gets it read by the vision/transcription harness first (`prepare-messages-for-model.ts`).
 - **Per-bot models:** in a workspace, its `workspace_harness_settings` row wins (`source: "workspace"`). Otherwise a worker bot inherits the defaults per harness unless it has a `bot_harness_settings` row (same fields as `harness_settings`, unique per bot and harness). `grabHarnessSetting({ harness, bot_id })` returns the bot's row (`source: "bot"`) or the default; the coordinator always gets the default. Every entry point takes `bot_id` and passes it on (text loop -> media reading/transcription), so a bot's run uses its own models throughout. Saved by `saveBotHarnessSetting` (`inherit` deletes the row); the page data is `grabBotHarnessOverview`. A bot's chat header has a ghost model icon (`(partials)/header-icon-button.tsx`; the text model and provider show under the bot's name) that opens a modal with every harness (`(partials)/bot-models-modal.tsx`); the modal and `/admin/bots/[bot_id]/models` both use `(partials)/bot-harness-form.tsx`. On the coordinator the modal edits the defaults themselves (`api/admin/harness/save-settings`, the same settings as Settings, under Models, without the providers): super admins only, the icon is disabled for everyone else. Every one of these wraps `settings/models/(partials)/harness-settings-form.tsx`: per harness a provider select first (`harness-provider-select.tsx`: any provider, one provider, or on a bot "Same as the default"), then the model select narrowed to it. Removing a provider (`deleteHarnessProvider`) puts default and bot settings that picked it or its models back on any provider (`save` prop; "Same as the default" shows when the overview item has `default`).
-- **Tools:** `HarnessTool` (built per run with its bot bound): own tools validate with a zod `schema`; tools described elsewhere pass a JSON schema as `parameters` and validate themselves. `run-tool-call.ts` reports bad calls and failures back to the model as `Error: ...`. Bot tools in `src/harness/tools/bot/`: `update_memory`, `update_instructions` (`grabBotTools`, every run), `start_task` and, for the coordinator with workers, `delegate_task` (`grabBotChatTools`, chat replies only; the job's `requested_by_bot_id` is the coordinator, and `relayJobToRequester` posts the worker's result or failure in its conversation, pushed as `relay` by `pushBotNotice`), `ask_user_to_take_over` (see Take-over), plus for the coordinator `assign_computer` (grant or revoke a worker's direct access, `add/remove-bot-to/from-computer`; access through a workspace stays and the result says so). `search_computers` (`src/harness/tools/computer/search-computers-tool.ts`, chat replies and tasks) runs one read-only command on all of a bot's computers at once over the sandbox REST API (`run-computer-command.ts`), each output under its `[computer:ID]`, secrets redacted, capped by `AppData.ComputerSearch*`.
+- **Tools:** `HarnessTool` (built per run with its bot bound): own tools validate with a zod `schema`; tools described elsewhere pass a JSON schema as `parameters` and validate themselves. `run-tool-call.ts` reports bad calls and failures back to the model as `Error: ...`. Bot tools in `src/harness/tools/bot/`: `update_memory`, `update_instructions` (`grabBotTools`, every run), `start_task` and, for the coordinator with workers, `delegate_task` (`grabBotChatTools`, chat replies only; the job's `requested_by_bot_id` is the coordinator, and `relayJobToRequester` posts the worker's result or failure in its conversation, pushed as `relay` by `pushBotNotice`), `ask_user_to_take_over` (see Take-over), plus for the coordinator `create_bot` (add a worker with its name, role and instructions, and join it to a workspace straight away) and, in its own chat, `add_bot_to_workspace` (put an existing worker in one of the user's workspaces) and `assign_computer` (grant or revoke a worker's direct access, `add/remove-bot-to/from-computer`; access through a workspace stays and the result says so). `search_computers` (`src/harness/tools/computer/search-computers-tool.ts`, chat replies and tasks) runs one read-only command on all of a bot's computers at once over the sandbox REST API (`run-computer-command.ts`), each output under its `[computer:ID]`, secrets redacted, capped by `AppData.ComputerSearch*`.
 - **MCP:** `src/harness/mcp/`: `connectMcpServer` (Streamable HTTP, SSE fallback), `grabMcpTools` (each server tool becomes a `HarnessTool` with its JSON schema), `mcpResultToText` (text as is, images read by the vision harness, `isError` thrown). Computers are reached this way: `openComputerTools` (`src/harness/tools/computer/`) connects to the computer's AIO sandbox at `grabComputerMcpUrl` (the `MAIN_COMPUTER_URL` app setting for the main computer, for a dev server outside docker, e.g. `http://localhost:8170`, else `http://<hostname>:<port>/mcp`, or its IP address when the hostname can't be reached), leaves out `ComputerMcpExcludedTools`, and sets the computer's envs (see Envs).
 - **Replies and tasks:** `run-bot-reply.ts` answers from the last `BotReplyHistoryMessages` messages (`botMessagesToHarness`) with `ChatReplyNote`, the bot's computers (`compose-computers-note.ts`: what they are and that they're reached through `start_task`) and the chat tools, at most `BotReplyMaxToolSteps` steps, and finishes silently if the bot already had the last word (`enqueueBotReply` reuses a pending reply, so a burst of messages gets one). `run-bot-task.ts` runs the brief (`compose-job-brief.ts`) with `TaskRunNote`, the bot tools and the job's computer tools, closing the MCP connection after. Retryable harness errors go back to the queue's backoff, the rest are `BotJobFatalError`.
 - **API:** `api/admin/harness/` (`save-provider` also syncs, `sync-provider`, `delete-provider`, `save-settings`), super admin only, each returning the fresh `grabHarnessOverview()` page data.