diff --git a/backend-java/src/main/java/com/tasteby/config/SecurityConfig.java b/backend-java/src/main/java/com/tasteby/config/SecurityConfig.java
index 10c2eaa..580549f 100644
--- a/backend-java/src/main/java/com/tasteby/config/SecurityConfig.java
+++ b/backend-java/src/main/java/com/tasteby/config/SecurityConfig.java
@@ -30,13 +30,14 @@ public class SecurityConfig {
             .authorizeHttpRequests(auth -> auth
                 // Public endpoints
                 .requestMatchers("/api/health").permitAll()
+                .requestMatchers("/api/version").permitAll()   // #338 — 빌드 정보 공개
                 .requestMatchers("/api/auth/**").permitAll()
                 .requestMatchers(HttpMethod.GET, "/api/restaurants/**").permitAll()
                 .requestMatchers(HttpMethod.GET, "/api/channels").permitAll()
                 .requestMatchers(HttpMethod.GET, "/api/search").permitAll()
                 .requestMatchers(HttpMethod.GET, "/api/restaurants/*/reviews").permitAll()
                 .requestMatchers("/api/stats/**").permitAll()
-                .requestMatchers(HttpMethod.GET, "/api/daemon/config").permitAll()
+                // #275 — /api/daemon/config는 admin-only로 변경 (이전 permitAll 제거)
                 // Everything else requires authentication (controller-level admin checks)
                 .anyRequest().authenticated()
             )
diff --git a/backend-java/src/main/java/com/tasteby/controller/ChannelController.java b/backend-java/src/main/java/com/tasteby/controller/ChannelController.java
index eec618a..a7cebb3 100644
--- a/backend-java/src/main/java/com/tasteby/controller/ChannelController.java
+++ b/backend-java/src/main/java/com/tasteby/controller/ChannelController.java
@@ -62,7 +62,8 @@ public class ChannelController {
         }
         try {
             String id = channelService.create(channelId, channelName, titleFilter);
-            cache.flush();
+            // #333 — 전체 flush 대신 channels 키만 evict (다른 모듈 캐시 보존)
+            cache.del(cache.makeKey("channels"));
             return Map.of("id", id, "channel_id", channelId);
         } catch (DataIntegrityViolationException e) {
             // #295 — 유니크 충돌을 메시지 문자열 매칭 대신 typed 예외로 감지 (제약명 변경에도 견고).
diff --git a/backend-java/src/main/java/com/tasteby/controller/HealthController.java b/backend-java/src/main/java/com/tasteby/controller/HealthController.java
index 735c34e..b220d7f 100644
--- a/backend-java/src/main/java/com/tasteby/controller/HealthController.java
+++ b/backend-java/src/main/java/com/tasteby/controller/HealthController.java
@@ -1,5 +1,6 @@
 package com.tasteby.controller;
 
+import org.springframework.beans.factory.annotation.Value;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RestController;
 
@@ -8,8 +9,20 @@ import java.util.Map;
 @RestController
 public class HealthController {
 
+    // #338 — 배포 시 set되는 빌드 정보. 미설정 시 "dev"로 표시.
+    @Value("${app.build.version:dev}")
+    private String version;
+
+    @Value("${app.build.commit:unknown}")
+    private String commit;
+
     @GetMapping("/api/health")
     public Map<String, String> health() {
         return Map.of("status", "ok");
     }
+
+    @GetMapping("/api/version")
+    public Map<String, String> version() {
+        return Map.of("version", version, "commit", commit);
+    }
 }
diff --git a/backend-java/src/main/resources/application.yml b/backend-java/src/main/resources/application.yml
index b997d83..acf899b 100644
--- a/backend-java/src/main/resources/application.yml
+++ b/backend-java/src/main/resources/application.yml
@@ -64,6 +64,11 @@ app:
     # 0.57은 cohere embed-v4 한국어 시맨틱 적합도 기준 경험값.
     max-distance: ${SEARCH_MAX_DISTANCE:0.57}
 
+  build:
+    # #338 — 배포 시 deploy.sh가 env로 주입. dev에서는 dev/unknown.
+    version: ${APP_VERSION:dev}
+    commit: ${APP_COMMIT:unknown}
+
   daemon:
     # 인스턴스 차원 스케줄러 활성화. dev/prod가 같은 DB를 공유하므로
     # dev .env에 DAEMON_ENABLED=false를 설정해 dev 폴링을 끄고 prod만 동작시킨다.
diff --git a/frontend/src/app/page.tsx b/frontend/src/app/page.tsx
index ff46e54..9ce6335 100644
--- a/frontend/src/app/page.tsx
+++ b/frontend/src/app/page.tsx
@@ -168,10 +168,15 @@ function findRegionFromCoords(
   }
   let best: { country: string; city: string } | null = null;
   let bestDist = Infinity;
+  // #320 — 유클리드 거리는 적도/극지에서 경도·위도의 실거리 차이가 커서 왜곡됨.
+  // cos(lat) 가중치(equirectangular approximation)로 위도 의존 보정.
+  const cosLat = Math.cos((lat * Math.PI) / 180);
   for (const g of groups.values()) {
     const cLat = g.lats.reduce((a, b) => a + b, 0) / g.lats.length;
     const cLng = g.lngs.reduce((a, b) => a + b, 0) / g.lngs.length;
-    const dist = (cLat - lat) ** 2 + (cLng - lng) ** 2;
+    const dLat = cLat - lat;
+    const dLng = (cLng - lng) * cosLat;
+    const dist = dLat * dLat + dLng * dLng;
     if (dist < bestDist) {
       bestDist = dist;
       best = { country: g.country, city: g.city };
diff --git a/frontend/src/components/MapView.tsx b/frontend/src/components/MapView.tsx
index 85db334..a3ad87e 100644
--- a/frontend/src/components/MapView.tsx
+++ b/frontend/src/components/MapView.tsx
@@ -209,6 +209,8 @@ function MapContent({ restaurants, selected, onSelectRestaurant, flyTo, activeCh
               zIndex={100}
             >
               <div
+                role="button"
+                aria-label={`${point_count}개 식당이 모인 클러스터, 클릭하면 확대됩니다`}
                 style={{
                   width: size,
                   height: size,
@@ -246,7 +248,10 @@ function MapContent({ restaurants, selected, onSelectRestaurant, flyTo, activeCh
             onClick={() => handleMarkerClick(r)}
             zIndex={isSelected ? 1000 : 1}
           >
-            <div style={{ display: "flex", flexDirection: "column", alignItems: "center", transition: "transform 0.2s ease", transform: isSelected ? "scale(1.15)" : "scale(1)", opacity: isClosed ? 0.5 : 1 }}>
+            <div
+              role="button"
+              aria-label={`${r.name}${isClosed ? ' (폐업)' : ''}, 클릭하면 상세 정보가 표시됩니다`}
+              style={{ display: "flex", flexDirection: "column", alignItems: "center", transition: "transform 0.2s ease", transform: isSelected ? "scale(1.15)" : "scale(1)", opacity: isClosed ? 0.5 : 1 }}>
               <div
                 style={{
                   padding: "4px 8px",
@@ -389,10 +394,15 @@ export default function MapView({ restaurants, selected, onSelectRestaurant, onB
         </button>
       )}
       {channelNames.length > 0 && (
-        <div className="absolute bottom-2 left-2 bg-surface/90 backdrop-blur-sm rounded-lg shadow px-2.5 py-1.5 flex flex-wrap gap-x-3 gap-y-1 text-[11px] z-10">
+        <div
+          role="region"
+          aria-label="채널 범례"
+          className="absolute bottom-2 left-2 bg-surface/90 backdrop-blur-sm rounded-lg shadow px-2.5 py-1.5 flex flex-wrap gap-x-3 gap-y-1 text-[11px] z-10"
+        >
           {channelNames.map((ch) => (
             <div key={ch} className="flex items-center gap-1">
               <span
+                aria-hidden="true"
                 className="inline-block w-2.5 h-2.5 rounded-full border"
                 style={{ backgroundColor: channelColors[ch].border, borderColor: channelColors[ch].border }}
               />