Add a Charging tab to the web app sidebar

Mirror the web-dashboard UI kit's charging screen: a map panel with
charger pins, an active-session card, and a nearby-stations list. Adds
the sidebar nav item, the /charging route, and the Charging view, plus
en/pl/da translations. Session and station data are presentational
placeholders until the server exposes charging telemetry.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Web App/web/src/App.vue

@@ -36,6 +36,7 @@ const userInitial = computed(() =>
 const nav = computed(() =>
   [
     { to: "/", label: t("nav.garage"), icon: "grid", exact: true },
+    { to: "/charging", label: t("nav.charging"), icon: "bolt" },
     { to: "/settings", label: t("nav.settings"), icon: "gear" },
     isAdmin.value ? { to: "/admin", label: t("nav.users"), icon: "users" } : null,
   ].filter(Boolean)
@@ -84,6 +85,8 @@ onBeforeUnmount(() => themeObserver?.disconnect());
         >
           <!-- garage -->
           <svg v-if="item.icon === 'grid'" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.75" class="h-5 w-5 shrink-0" :style="active(item) ? 'color:#60A5FA' : ''"><rect x="3" y="3" width="7" height="7" rx="1.5"/><rect x="14" y="3" width="7" height="7" rx="1.5"/><rect x="3" y="14" width="7" height="7" rx="1.5"/><rect x="14" y="14" width="7" height="7" rx="1.5"/></svg>
+          <!-- charging -->
+          <svg v-else-if="item.icon === 'bolt'" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.75" class="h-5 w-5 shrink-0" :style="active(item) ? 'color:#60A5FA' : ''"><path stroke-linecap="round" stroke-linejoin="round" d="M13 2 4.5 13.5H11l-1 8.5 8.5-11.5H12z"/></svg>
           <!-- settings -->
           <svg v-else-if="item.icon === 'gear'" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.75" class="h-5 w-5 shrink-0" :style="active(item) ? 'color:#60A5FA' : ''"><path stroke-linecap="round" stroke-linejoin="round" d="M9.6 3.6 9 6a7.5 7.5 0 0 0-1.7 1L5 6.3l-2 3.4 2 1.5a7.6 7.6 0 0 0 0 2l-2 1.5 2 3.4 2.3-.7c.5.4 1.1.8 1.7 1l.6 2.4h4l.6-2.4c.6-.2 1.2-.6 1.7-1l2.3.7 2-3.4-2-1.5a7.6 7.6 0 0 0 0-2l2-1.5-2-3.4-2.3.7A7.5 7.5 0 0 0 15 6l-.6-2.4z"/><circle cx="12" cy="12" r="2.6"/></svg>
           <!-- users -->