Add ghost text autocomplete location search to homepage hero

Replaces community dropdown with text input supporting city/ZIP search:
- Ghost text autocomplete shows inline suggestion as user types
- Tab to accept, auto-fill on blur, Enter uses partial match
- Geolocation button for "Use My Location" searches
- AJAX endpoint returns MN/IA cities and zipcodes with 1-hour cache
- MLS query now supports lat/lng/radius for distance-based filtering
- Updated Census Bureau 2023 Gazetteer data (32,329 US cities)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

wp-content/plugins/mls-by-hansonxyz/data/README.md

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+# Geo Data Sources
+
+## us_cities.csv
+
+US Census Bureau 2023 Gazetteer Places File
+
+- **Source:** https://www2.census.gov/geo/docs/maps-data/data/gazetteer/2023_Gazetteer/2023_Gaz_place_national.zip
+- **Records:** 32,329 cities/places
+- **Last Updated:** December 2025
+- **Format:** CSV with columns: ID, STATE_CODE, STATE_NAME, CITY, COUNTY, LATITUDE, LONGITUDE
+
+## us_zipcodes.csv
+
+US ZIP code centroids with latitude/longitude coordinates.
+
+- **Records:** 33,144 ZIP codes
+- **Format:** CSV with columns: zipcode, latitude, longitude