feat(planner): restyle sidebar on tokens (waypoints, notes, days)

Migrate the whole sidebar surface onto the design system:

- SidebarTabs: token tab bar, sage active indicator.
- WaypointSidebar: token surfaces/text; sage number badges; overnight
  marker uses the Badge (stop tone) primitive; route summary + stats
  footer in Geist Mono; destructive delete signalled via bg-nogo.
- NotesPanel + DayBreakdown headers/rows on tokens.
- i18n the previously-hardcoded empty-state string (en + de).

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

packages/i18n/src/locales/de.ts

@@ -91,6 +91,7 @@ export default {
     waypoint: {
       notePlaceholder: "Notiz hinzufügen…",
       noteCounter: "{{count}} / {{max}}",
+      emptyState: "Klicke auf die Karte, um Wegpunkte hinzuzufügen",
     },
     nearbyPoi: {
       heading: "In der Nähe",

packages/i18n/src/locales/en.ts

@@ -91,6 +91,7 @@ export default {
     waypoint: {
       notePlaceholder: "Add a note...",
       noteCounter: "{{count}} / {{max}}",
+      emptyState: "Click on the map to add waypoints",
     },
     nearbyPoi: {
       heading: "Nearby",