feat(shell): collapsible sidebar, account menu, and phone drawer

The Dashboard's shell now follows DESIGN.md §4 (ADR 0058):

- A collapsible left sidebar replaces the header-and-column layout. It
  is icons and labels when expanded and icons only when collapsed; each
  collapsed item keeps its name, visually hidden, and shows a tooltip
  on hover and on keyboard focus (WCAG 2.2 §1.4.13). The Overview comes
  first, then the server's groups and modules. There is no top bar.
- The expanded/collapsed choice is remembered in this browser's
  localStorage, behind a SidebarPreference interface that a synced
  store can replace later.
- An account menu at the bottom of the sidebar follows the WAI-ARIA menu
  button pattern and offers only Sign out, which now lives there rather
  than in the header.
- On phones (below 48em) the same navigation opens in a modal drawer:
  the page behind it is inert and focus is trapped inside it. Escape,
  its close button, and the backdrop close it and return focus to the
  menu button. Choosing a page closes it and focuses the page. Changing
  layout keeps the route, the desktop mode, and the mounted module.
- Lucide (lucide-react 1.48.0, shell only) is Ekklesia's icon
  vocabulary. Every module shows one generic icon until manifest v9
  lets modules declare their own; there is no per-module icon map.
- The identity slot is a neutral placeholder with no inputs, waiting
  for branding (#101).

The tooltip, menu, and drawer stay shell-local until a second consumer
needs them (ADR 0039). The deploy smoke now signs out through the
account menu, and drives the drawer at phone size in a real browser.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

README.md

@@ -916,8 +916,18 @@ each installed module's `/<module-id>`; any other top-level path is its sanitize
 the platform's own top-level names (`account`, `api`, `assets`, `display`, `settings`), and
 discovery refuses a module that uses one. An installed module that is disabled shows a host-owned
 *This page isn't available* rather than loading anything. A module's own
-sub-pages, Settings and Account pages, the sidebar redesign, and returning to the workflow a Settings
-link came from are later Stage 1 work.
+sub-pages, Settings and Account pages, and returning to the workflow a Settings link came from are
+later Stage 1 work.
+
+The Dashboard's **shell** follows DESIGN.md §4
+([ADR 0058](docs/architecture/decisions/0058-dashboard-shell-navigation-and-lucide-icons.md)): a
+collapsible left sidebar — icons and labels expanded, icons with accessible tooltips collapsed, the
+choice remembered in this browser — with the Overview first, the server's groups and modules below it,
+and an account menu anchored at the bottom (Sign out, for now). There is no top bar. On a phone the
+same navigation opens in a modal drawer with focus trapped inside it, Escape and the backdrop closing
+it, and focus returned to the menu button. Lucide is Ekklesia's icon vocabulary; until modules can
+declare their own icon (manifest v9), every module shows one generic icon. Church branding in the
+sidebar's identity slot is still to come.
 
 ## Quick start