Add Google Maps ProviderMap organism with clustering + popup flow

Introduces a full Google-Maps-backed provider map for the arrangement
wizard's ProvidersStep. Clicking a pin morphs it into a MapPopup at
the same coord; pins within 70px of each other collapse into a cluster
(ceiling at zoom 13) that opens a ClusterPopup list on click. Row
clicks pan + zoom the map to the provider and open their MapPopup.
Map-background click routes through an exit transition that fades the
popup out before reappearing the pin, via a matching fade-in keyframe
on the atom markers.

Key additions:
- @vis.gl/react-google-maps + @googlemaps/markerclusterer deps
- ClusterMarker atom (count badge; verified / unverified palettes)
- ClusterPopup molecule (image-free rows; verified icon aligned to
  name; right-aligned "From $X" column; verified-first sort)
- ProviderMap organism (APIProvider + Map + imperative AdvancedMarker
  layer via createRoot for clusterer compatibility)

Component changes:
- MapPin: promoted verified palette (brand-700); name now required;
  name-only and price-only variants dropped; active prop removed in
  favour of organism-level state; SVG nub with fill+stroke replaces
  the CSS border-triangle trick so the outline is continuous
- MapPopup: `exiting` prop drives close animation; click events stop
  propagation so the map's onClick can't clear state mid-interaction
- ProviderData type gains optional `coords`; demo fixtures populated
  with real NSW/QLD lat/lng for all 7 providers
- ProvidersStep demo route wires ProviderMap into the mapPanel slot

Memory:
- docs/memory/component-registry updated (ClusterMarker, ClusterPopup,
  ProviderMap added; MapPin + MapPopup refined; MapCard retired)
- docs/memory/session-log captures arc across 2026-04-21/22 and flags
  next-session work: ProvidersStep polish, mobile layout for list-map
  WizardLayout, and demo deploy

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

package.json

@@ -27,9 +27,11 @@
   "dependencies": {
     "@emotion/react": "^11.13.0",
     "@emotion/styled": "^11.13.0",
+    "@googlemaps/markerclusterer": "^2.6.2",
     "@mui/icons-material": "^5.16.0",
     "@mui/material": "^5.16.0",
     "@mui/system": "^5.16.0",
+    "@vis.gl/react-google-maps": "^1.8.3",
     "react": "^18.3.0",
     "react-dom": "^18.3.0",
     "react-router-dom": "^7.14.1",