feat(geocoding): migrate to Places API (New), add server-side geocoding for agents

[jhb-dev]

Summary

Places API (New) Migration

• Replace react-google-places-autocomplete with Google's Places API (New) AutocompleteSuggestion API and Payload's built-in ReactSelect
• Rename _googlePlacesData field to _meta with a clean flat schema: { name, formattedAddress, googlePlaceId, types }
• Rename geoDataFieldOverride config option to locationMetaOverride
• Add JSON schema validation to the meta field
• Add migration script for existing data (migrations/migrate-to-0.3.0.ts)
• Extract Google Maps loader into separate utility file

Server-Side Geocoding for AI Agents / API

• GET /api/geocoding-plugin/search?q=<address> — authenticated endpoint with custom access function support (geocodingEndpoint.access)
• {field}_address virtual field — every geocodingField includes a hidden virtual _address text field; submitting an address string via the API auto-geocodes it and populates the point + _meta fields
• geocodeAddress() exported service — server-side Google Geocoding HTTP API client, usable in custom code
• Both field hooks share a single API call via req.context promise caching (Payload processes row fields in parallel)
• README section: "Usage with AI Agents / API"

Test Infrastructure

• Full integration test setup with SQLite (following pages plugin pattern)
• Articles collection with Lexical editor block for testing geocoding in blocks
• test-geocoding CI job added to workflow
• 27 unit tests + 10 integration tests

Breaking Changes

• Places API (New) must be enabled in Google Cloud project
• _googlePlacesData field renamed to _meta with new data shape
• geoDataFieldOverride config renamed to locationMetaOverride
• react-google-places-autocomplete dependency removed

Test plan

• 27 unit tests (service, endpoint, hooks, plugin config, field config)
• 10 integration tests against real Payload + SQLite:
  • Field structure: point/meta in top-level, group, and array fields
  • Server-side geocoding: auto-geocode via _address on create and update
  • Lexical block: geocoding field inside a Lexical editor block
  • Endpoint registration verification
• Type check passes (tsc --noEmit)
• Lint passes (0 errors)
• Formatting clean (prettier)
• CI test-geocoding job passes
• Verify autocomplete dropdown shows suggestions
• Verify selecting a place stores coordinates in point field
• Verify _meta field stores { name, formattedAddress, googlePlaceId, types }
• Verify clearing selection resets both fields
• Verify migration script transforms old data correctly