Add map overnight markers, day labels, and context menu

- Overnight waypoints render amber-brown (#8B6D3A) with moon icon
- Day boundary labels (white pill "Day N · X km") at overnight waypoints
- Right-click middle waypoints toggles overnight (first/last still delete)
- Wire days prop through SessionView → PlannerMap

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/planner/app/components/SessionView.tsx

@@ -285,7 +285,7 @@ export function SessionView({ sessionId, callbackUrl, callbackToken, returnUrl,
                 </div>
               }
             >
-              <PlannerMap yjs={yjs} onRouteRequest={requestRoute} highlightPosition={highlightPosition} onImportError={(msg) => addToast(msg, "error")} />
+              <PlannerMap yjs={yjs} onRouteRequest={requestRoute} highlightPosition={highlightPosition} onImportError={(msg) => addToast(msg, "error")} days={days} />
             </Suspense>
           </div>
           <Suspense fallback={null}>