Add a persistent left sidebar to the signed-in layout

App.vue now renders a left AppSidebar beside the routed view for any
requiresAuth page, staying mounted as you move between the dashboard and
projects. The sidebar has a Dashboard link (icon), a divider, the project list
(each an icon link, current page highlighted via RouterLink active-class), and a
compact new-project form that jumps to the created project.

- New /dashboard route + DashboardView ("under construction"); / and unknown
  paths redirect there. HomeView removed -- its project list and form moved into
  the sidebar.
- <RouterView :key="route.path"> so navigating project -> project via the
  sidebar remounts and reloads instead of reusing the instance.
- Signed-out routes (login/register/verify-email) render without the sidebar.

Icons are inline SVG -- no new dependency.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

web/README.md

@@ -35,12 +35,27 @@ src/stores/auth.ts      Pinia store: token in localStorage, register/login/fetch
 src/stores/projects.ts  Pinia store: the user's projects (fetch + create)
 src/stores/cards.ts     Pinia store: one project's cards (CRUD + reorderColumn)
 src/lib/api.ts          fetch wrapper, bearer token, typed ApiError
+src/components/AppSidebar.vue left nav: Dashboard link, divider, project list + new-project form
 src/components/CardRow.vue    editable text + status chip + delete, one card
 src/components/KanbanCard.vue small draggable card for the board columns
-src/views/              HomeView, ProjectView, LoginView, RegisterView,
+src/views/              DashboardView, ProjectView, LoginView, RegisterView,
                         ProfileView, VerifyEmailView
 ```
 
+## Layout
+
+Signed-in "app" routes (`meta.requiresAuth`) render inside a persistent shell:
+the top bar, then a left **sidebar** (`AppSidebar.vue`) beside the routed view.
+The sidebar stays mounted across navigation — it holds a **Dashboard** link, a
+divider, the project list, and a compact new-project form (creating one jumps to
+it). The current page is highlighted via RouterLink's `active-class`.
+`<RouterView :key="route.path">` remounts the view on every path change so
+sidebar → project → project navigation always does a fresh load.
+
+`/` redirects to `/dashboard` (`DashboardView.vue`, an "under construction"
+placeholder). Signed-out routes (`/login`, `/register`, `/verify-email`) render
+without the sidebar.
+
 ## Project detail
 
 `/projects/:id` shows one project. It renders on a **full-width** layout (the
@@ -48,7 +63,7 @@ route sets `meta.wide`, which widens `.app__main` in `App.vue`). The title and
 description are inline-editable (saved on blur via `PATCH /api/projects/:id`; the
 description shows an "Add a description" placeholder when empty). A **Manage**
 menu (top right) has a **Delete project** action that opens a confirmation modal;
-confirming calls `DELETE /api/projects/:id` and returns to the all-projects view.
+confirming calls `DELETE /api/projects/:id` and returns to the dashboard.
 
 Below the header are two tabs (local `activeTab` state, `v-show` so both stay
 mounted):