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>

src/demo/shared/fixtures/providers.ts

@@ -20,6 +20,7 @@ export const providers: DemoProvider[] = [
     reviewCount: 7,
     startingPrice: 1800,
     distanceKm: 2.3,
+    coords: { lat: -34.1074, lng: 141.9166 },
     description:
       'H.Parsons delivers premium funeral services with exceptional care and support, guiding families through every step with empathy and expertise.',
   },
@@ -35,6 +36,7 @@ export const providers: DemoProvider[] = [
     reviewCount: 23,
     startingPrice: 2450,
     distanceKm: 5.1,
+    coords: { lat: -34.487, lng: 150.897 },
   },
   {
     id: 'wollongong-city',
@@ -46,6 +48,7 @@ export const providers: DemoProvider[] = [
     reviewCount: 15,
     startingPrice: 3400,
     distanceKm: 6.8,
+    coords: { lat: -34.4278, lng: 150.8931 },
   },
   {
     id: 'killick',
@@ -59,6 +62,7 @@ export const providers: DemoProvider[] = [
     reviewCount: 15,
     startingPrice: 3100,
     distanceKm: 8.4,
+    coords: { lat: -26.5408, lng: 151.8388 },
   },
   {
     id: 'mackay',
@@ -72,6 +76,7 @@ export const providers: DemoProvider[] = [
     reviewCount: 87,
     startingPrice: 2800,
     distanceKm: 18.2,
+    coords: { lat: -33.3644, lng: 151.3728 },
   },
   {
     id: 'mannings',
@@ -85,6 +90,7 @@ export const providers: DemoProvider[] = [
     reviewCount: 31,
     startingPrice: 2600,
     distanceKm: 22.0,
+    coords: { lat: -36.6742, lng: 149.8417 },
   },
   {
     id: 'botanical',
@@ -96,6 +102,7 @@ export const providers: DemoProvider[] = [
     reviewCount: 8,
     startingPrice: 5200,
     distanceKm: 15.0,
+    coords: { lat: -33.8988, lng: 151.1794 },
   },
 ];