Extends NearbyStationsRequest validation to accept `sort=updated` and `sort=brand`. Updates StationController to use match expression with dedicated closures: 'updated' sorts by price_effective_at descending (newest first), 'brand' sorts alphabetically by brand_name, with existing price and distance options.
Extends NearbyStationsRequest to accept `postcode` (full or outcode) as an alternative to lat/lng. PostcodeService resolves it via postcodes.io and falls through to coordinates. Also adds SearchResource to the Filament admin panel for viewing logged search activity with fuel type filter and price/distance stats columns. Includes SQLite GREATEST/LEAST function polyfills in AppServiceProvider for test compatibility.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
