feat(plugins): pass the dashboard's spotlight trip id to widget plugins

Widget plugins now receive the current (spotlight) trip id in their bridge
context, so a widget like Trip Countdown can show a real countdown instead of
the empty state.

client/src/pages/DashboardPage.tsx

@@ -237,7 +237,7 @@ export default function DashboardPage(): React.ReactElement {
               {showCollections && <CollectionsWidget onOpen={() => navigate('/collections')} />}
               {showTimezones && <TimezoneTool locale={locale} />}
               {showUpcoming && <UpcomingTool items={upcoming} locale={locale} onOpen={(tripId) => navigate(`/trips/${tripId}`)} />}
-              <PluginWidgets plugins={widgetPlugins} />
+              <PluginWidgets plugins={widgetPlugins} tripId={spotlight ? String(spotlight.id) : null} />
             </aside>
           )}
         </main>