Add flexible listing_type support and last_update_date field

- Add support for str, list[str], and None as listing_type values
  - Single string: maintains backward compatibility (e.g., "for_sale")
  - List of strings: returns properties matching ANY status (OR logic)
  - None: returns all property types (omits status filter)

- Expand ListingType enum with all GraphQL HomeStatus values
  - Add OFF_MARKET, NEW_COMMUNITY, OTHER, READY_TO_BUILD

- Add last_update_date field support
  - Add to GraphQL query, Property model, and processors
  - Add to sort validation and datetime field sorting
  - Field description: "Last time the home was updated"

- Update GraphQL query construction to support status arrays
  - Single type: status: for_sale
  - Multiple types: status: [for_sale, sold]
  - None: omit status parameter entirely

- Update validation logic to handle new parameter types

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

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

homeharvest/core/scrapers/realtor/queries.py

@@ -10,6 +10,7 @@ _SEARCH_HOMES_DATA_BASE = """{
     last_sold_price
     last_sold_date
     last_status_change_date
+    last_update_date
     list_price
     list_price_max
     list_price_min