# Task 1942 — Sub-account switcher moves to the sidebar brand head

Design doc. Source task: `.tasks/1942-subaccount-switcher-moves-to-sidebar-brand-head.md`.

## Goal

Open the sub-account picker by clicking the account name at the top of the sidebar, not from the footer kebab. Remove the switcher from the footer menu.

## Resolved decisions (brainstorm)

1. **Click target:** the whole brand head (`side-brand`: icon + two-line lockup) becomes one button when the switcher is available.
2. **Affordance:** a small down-chevron renders after the business name to signal the dropdown.
3. **Close:** re-clicking the head toggles it shut, and a transparent full-screen scrim behind the panel closes it on any outside click. Mirrors the footer-menu scrim it replaces.

## Availability gate (unchanged from today)

Switcher is available only when `subAccounts.length > 1 && Boolean(onSwitchAccount)`. Unavailable → the head stays a plain non-interactive `<div>`, no chevron, no picker. This is the current `switcherAvailable` gate, moved from `AccountMenu` to `Sidebar`.

## Components and flow

- **`Sidebar.tsx`** owns `switcherOpen` state. The brand head renders as `<button aria-haspopup="menu" aria-expanded={switcherOpen}>` when available, else the current `<div>`. Click toggles `switcherOpen`; the closed→open transition fires `refreshAccounts?.()` and emits `[admin-ui] op=subaccount-switcher-toggle anchor=brand-head open=<bool> available=<bool> accounts=<N>`. `SubAccountPicker` renders inside `.side-brand`, anchored beneath it, with a sibling scrim that closes on click.
- **`AccountMenu.tsx`** loses the `switcherAvailable`/`switcherOpen` block, the `SubAccountPicker` import, and the five switcher props. `UserRound` import dropped if otherwise unused.
- **`globals.css`** gives `.side-brand` `position: relative` and re-anchors `.sub-account-picker-panel` left-aligned under the head (drop the retired header-title `translateX(-50%)` centering). Adds `.side-brand` button-reset styling (transparent, inherit, pointer) and the chevron. Deletes the dead `.side-foot-menu .sub-account-picker-panel` / `-list` overrides.

## Collapsed rail (edge, in scope to not break)

When `sidebar-collapsed`, existing CSS hides `.side-brand-lockup` (name + chevron), leaving only the icon. The head-button still functions on the icon, but no new collapsed affordance is added (per task out-of-scope). The picker anchors under `.side-brand` in both states.

## Testing

vitest + jsdom (Node 22). New `Sidebar` test: available → head is a button, click mounts the picker and fires `refreshAccounts`, re-click closes; unavailable → not a button, no picker. `AccountMenu.test.tsx`: no "Switch account", switcher props dropped. `SubAccountPicker.test.tsx` unchanged.

## Out of scope

`SubAccountPicker` internals, the switch mechanism, other `AccountMenu` items, a dedicated collapsed-rail affordance, maxy-lite, Task 1940's mobile lite tab bar.