UX improvements: mobile bottom sheet, cuisine taxonomy, search enhancements

- Add BottomSheet component for Google Maps-style restaurant detail on mobile
  (3-snap drag: 40%/55%/92%, velocity-based close, backdrop overlay)
- Mobile map mode now full-screen with bottom sheet overlay for details
- Collapsible filter panel on mobile with active filter badge count
- Standardized cuisine taxonomy (46 categories: 한식|국밥, 일식|스시 etc.)
  with LLM remap endpoint and admin UI button
- Enhanced search: keyword search now includes foods_mentioned + video title
- Search results include channels array for frontend filtering
- Channel filter moved to frontend filteredRestaurants (not API-level)
- LLM extraction prompt updated for pipe-delimited region + cuisine taxonomy
- Vector rebuild endpoint with rich JSON chunks per restaurant
- Geolocation-based auto region selection on page load
- Desktop filters split into two clean rows

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/components/RestaurantList.tsx

@@ -1,6 +1,7 @@
 "use client";
 
 import type { Restaurant } from "@/lib/api";
+import { getCuisineIcon } from "@/lib/cuisine-icons";
 
 interface RestaurantListProps {
   restaurants: Restaurant[];
@@ -31,7 +32,10 @@ export default function RestaurantList({
             selectedId === r.id ? "bg-blue-50 border-l-2 border-blue-500" : ""
           }`}
         >
-          <h4 className="font-medium text-sm">{r.name}</h4>
+          <h4 className="font-medium text-sm">
+            <span className="mr-1">{getCuisineIcon(r.cuisine_type)}</span>
+            {r.name}
+          </h4>
           <div className="flex gap-2 mt-1 text-xs text-gray-500">
             {r.cuisine_type && <span>{r.cuisine_type}</span>}
             {r.region && <span>{r.region}</span>}