feat: account pool per tool with groups and a Cursor pool; update runs in the background

- The update dialog can be closed while an update applies: it keeps running,
  the page still reloads itself when the new server is up, and a failure
  re-opens the dialog with its error.
- Account pool card: one tab per AI tool (Claude Code, Codex, Cursor CLI,
  Oh My Pi, and every other installed tool, which says it has no pool),
  accounts as cards with 5-hour and weekly quota shown as what is LEFT plus
  their reset times, and the saved profiles of Settings → AI tools →
  Profiles as cards with "Share to pool".
- Cursor account pool (server/lib/cursor-pool.js): Cursor API keys handed to
  a cursor-agent pane only through tmux -e CURSOR_API_KEY;
  `agenthub accounts add <name> --tool cursor`.
- Pool groups (server/lib/pool-groups.js, /api/accounts/groups): a group's
  members run only on its accounts of each tool, a user in no group on the
  accounts no group lists, a pin still wins. account_pins loses its tool
  CHECK (rebuilt, pins kept); three new tables.
- Oh My Pi login sharing can be switched from its pool tab too.

docs/CLI.md

@@ -108,7 +108,7 @@ The CLI talks to the local dashboard server — **API-backed commands require it
 | `agenthub server install-system [--dry-run\|--uninstall]` | **One Linux user per account** (S3). Run as the account that runs the dashboard, never as root: it runs `scripts/server/install-system.sh` through one `sudo`. That script creates the groups, `/srv/agenthub/users`, `/opt/agenthub`, the sudoers file, the member hooks and `hidepid`, and installs the system unit `agenthub.service`. The command then points the unit at this install, writes `AGENTHUB_USERS_ROOT`, and moves the dashboard from the `systemd --user` unit to the system one (panes stay). `--dry-run` prints the sudo command; `--uninstall` goes back to the user unit. See [SERVER-MODE.md](SERVER-MODE.md#one-linux-user-per-account) |
 | `agenthub server tools` | One Linux user per account: publish this install's scripts and every installed AI tool under `/opt/agenthub` (`tools/bin/<command>`), where every account's pane runs them. The server also does this at start and after each install or update. Prints each tool's shared copy, or why it could not be shared |
 | `agenthub server off` / `agenthub server status` | Back to local mode (accounts kept) / show the mode and account count |
-| `agenthub accounts list\|add <name>\|remove <name>` | The **Claude account pool**: new Claude sessions spread over these accounts (each a `claude setup-token` token, typed hidden or read from stdin). `list` shows live panes, $ and tokens in the last 5 h / 7 d, and quota. With `--tool codex` the same for the **Codex account pool**: `add <name> --tool codex --api-key` (key typed hidden or on stdin) or `--from <dir>` (a `codex login` home or its `auth.json`). `pin <account> <user>` / `unpin <user>` (add `--tool codex` for Codex) switches one user's sessions to that account (a Claude login goes into their home at once, running sessions follow without a restart) (server mode; `list` shows a `pinned` column). See [SERVER-MODE.md](SERVER-MODE.md#claude-account-pool) |
+| `agenthub accounts list\|add <name>\|remove <name>` | The **Claude account pool**: new Claude sessions spread over these accounts (each a `claude setup-token` token, typed hidden or read from stdin). `list` shows live panes, $ and tokens in the last 5 h / 7 d, and quota. With `--tool codex` the same for the **Codex account pool**: `add <name> --tool codex --api-key` (key typed hidden or on stdin) or `--from <dir>` (a `codex login` home or its `auth.json`). With `--tool cursor` the **Cursor account pool**: `add <name> --tool cursor` (a Cursor API key, typed hidden or on stdin). `pin <account> <user>` / `unpin <user>` (add `--tool codex` or `--tool cursor`) switches one user's sessions to that account (a Claude login goes into their home at once, running sessions follow without a restart) (server mode; `list` shows a `pinned` column). See [SERVER-MODE.md](SERVER-MODE.md#claude-account-pool) |
 | `agenthub users list\|add <name> [--role admin\|analyst\|developer]\|passwd <name>\|role <name> <role>\|disable <name>\|enable <name>\|provision <name>\|--all\|assign <workspace id> <name>\|audit [--limit N]` | Server mode's accounts, written straight to the database. Once `install-system` ran, `add` first creates the Linux user `ah-<name>`; a name must then be lower case: a letter, then up to 28 letters, digits, `_` or `-`. `disable`/`enable` lock or unlock that Linux user too, and `provision` gives users made earlier their Linux user (idempotent); `assign` gives a workspace made before server mode an owner; `audit` lists admin/analyst reads of developers' sessions. Inside a dashboard pane in server mode, every command acts as the workspace's owner through the pane's `AGENTHUB_PANE_TOKEN`. A password is typed hidden twice, or read from the first line of stdin |
 
 ### Interactive REPL