Fix map disappearing when selecting a business

Add phx-update="ignore" to prevent LiveView from overwriting the
Leaflet map container when re-rendering after business selection.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

lib/localspot_web/live/business_live/map.ex

@@ -44,6 +44,7 @@ defmodule LocalspotWeb.BusinessLive.Map do
         id="map-container"
         class="w-full h-[600px] rounded-lg overflow-hidden relative"
         phx-hook="LeafletMap"
+        phx-update="ignore"
         data-businesses={Jason.encode!(map_businesses(@businesses))}
         data-center={Jason.encode!(%{lat: 39.9612, lng: -82.9988})}
         data-zoom="12"