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/lib/cuisine-icons.ts

@@ -0,0 +1,49 @@
+/**
+ * Cuisine type → icon mapping.
+ * Works with "대분류|소분류" format (e.g. "한식|국밥/해장국").
+ */
+
+const CUISINE_ICON_MAP: Record<string, string> = {
+  "한식": "🍚",
+  "일식": "🍣",
+  "중식": "🥟",
+  "양식": "🍝",
+  "아시아": "🍜",
+  "기타": "🍴",
+};
+
+// Sub-category overrides for more specific icons
+const SUB_ICON_RULES: { keyword: string; icon: string }[] = [
+  { keyword: "회/횟집", icon: "🐟" },
+  { keyword: "해산물", icon: "🦐" },
+  { keyword: "삼겹살/돼지구이", icon: "🥩" },
+  { keyword: "소고기/한우구이", icon: "🥩" },
+  { keyword: "곱창/막창", icon: "🥩" },
+  { keyword: "닭/오리구이", icon: "🍗" },
+  { keyword: "스테이크", icon: "🥩" },
+  { keyword: "햄버거", icon: "🍔" },
+  { keyword: "피자", icon: "🍕" },
+  { keyword: "카페/디저트", icon: "☕" },
+  { keyword: "베이커리", icon: "🥐" },
+  { keyword: "치킨", icon: "🍗" },
+  { keyword: "주점/포차", icon: "🍺" },
+  { keyword: "이자카야", icon: "🍶" },
+  { keyword: "라멘", icon: "🍜" },
+  { keyword: "국밥/해장국", icon: "🍲" },
+  { keyword: "분식", icon: "🍜" },
+];
+
+const DEFAULT_ICON = "🍴";
+
+export function getCuisineIcon(cuisineType: string | null | undefined): string {
+  if (!cuisineType) return DEFAULT_ICON;
+
+  // Check sub-category first
+  for (const rule of SUB_ICON_RULES) {
+    if (cuisineType.includes(rule.keyword)) return rule.icon;
+  }
+
+  // Fall back to main category (prefix before |)
+  const main = cuisineType.split("|")[0];
+  return CUISINE_ICON_MAP[main] || DEFAULT_ICON;
+}