fix(rework): long-op timeout, dedup query, clearer error, logging

Review follow-ups (safe fixes):
- pythonRestTemplate bean (10min read timeout) for /transcribe and /render so
  ffmpeg encoding / Whisper don't hit the shared 120s timeout; resolved by bean
  name so existing restTemplate injections are unaffected
- getScriptData: fetch the script row once instead of 3 separate queries
- renderTrimmed "no segments" now IllegalArgumentException (400 + visible message)
  instead of IllegalStateException swallowed as generic 500
- ProductionService: System.out.println -> log.info (3x)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/main/java/com/hlab/yanalyst/domain/channel/ChannelService.java

@@ -34,6 +34,7 @@ public class ChannelService {
 
     private final ChannelRepository channelRepository;
     private final RestTemplate restTemplate;
+    private final RestTemplate pythonRestTemplate; // 전사/렌더 등 장시간 호출용(긴 read timeout). 빈 이름으로 구분 주입.
     private final ObjectMapper objectMapper;
 
     private final ChannelVideoRepository channelVideoRepository;
@@ -410,7 +411,7 @@ public class ChannelService {
             }
 
             HttpEntity<MultiValueMap<String, Object>> request = new HttpEntity<>(body, headers);
-            ResponseEntity<String> response = restTemplate.postForEntity(apiUrl, request, String.class);
+            ResponseEntity<String> response = pythonRestTemplate.postForEntity(apiUrl, request, String.class);
 
             if (!response.getStatusCode().is2xxSuccessful() || response.getBody() == null) {
                 throw new RuntimeException("Transcribe API failed with status: " + response.getStatusCode());
@@ -479,7 +480,8 @@ public class ChannelService {
     public byte[] renderTrimmed(Long channelVideoId, MultipartFile file, double pad, double minGap, double speed) {
         List<ScriptSegment> segments = getSegments(channelVideoId);
         if (segments.isEmpty()) {
-            throw new IllegalStateException("세그먼트가 없습니다. 먼저 전사를 실행하세요.");
+            // 사용자에게 이유가 보이도록 400(IllegalArgumentException → GlobalExceptionHandler 가 메시지 노출).
+            throw new IllegalArgumentException("세그먼트가 없습니다. 먼저 영상 업로드·전사를 실행하세요.");
         }
         KeepIntervalPlanner.Plan plan = KeepIntervalPlanner.plan(segments, pad, minGap);
 
@@ -494,7 +496,7 @@ public class ChannelService {
             body.add("speed", String.valueOf(speed));
 
             HttpEntity<MultiValueMap<String, Object>> request = new HttpEntity<>(body, headers);
-            ResponseEntity<byte[]> response = restTemplate.postForEntity(apiUrl, request, byte[].class);
+            ResponseEntity<byte[]> response = pythonRestTemplate.postForEntity(apiUrl, request, byte[].class);
             if (!response.getStatusCode().is2xxSuccessful() || response.getBody() == null) {
                 throw new RuntimeException("Render API failed with status: " + response.getStatusCode());
             }

src/main/java/com/hlab/yanalyst/domain/channel/ChannelVideoCurationService.java

@@ -91,17 +91,16 @@ public class ChannelVideoCurationService {
     /** 스크립트 전체(평문 + 영상 싱크 세그먼트) 조회. 에디터의 세그먼트 리스트용. */
     public Map<String, Object> getScriptData(Long videoId) {
         ChannelVideo v = find(videoId);
-        String transcript = channelVideoScriptRepository.findFirstByVideoIdOrderByIdDesc(v.getVideoId())
-                .map(ChannelVideoScript::getTranscript)
+        ChannelVideoScript script = channelVideoScriptRepository
+                .findFirstByVideoIdOrderByIdDesc(v.getVideoId())
                 .orElse(null);
-        String language = channelVideoScriptRepository.findFirstByVideoIdOrderByIdDesc(v.getVideoId())
-                .map(ChannelVideoScript::getLanguage)
-                .orElse(null);
-        List<ScriptSegment> segments = channelService.getSegments(v.getId());
+        String transcript = (script != null) ? script.getTranscript() : null;
+        List<ScriptSegment> segments = (script != null)
+                ? channelService.parseSegments(script.getSegmentsJson()) : List.of();
 
         Map<String, Object> result = new LinkedHashMap<>();
         result.put("hasScript", transcript != null);
-        result.put("language", language);
+        result.put("language", (script != null) ? script.getLanguage() : null);
         result.put("transcript", transcript == null ? "" : transcript);
         result.put("segments", segments);
         return result;

src/main/java/com/hlab/yanalyst/domain/production/ProductionService.java

@@ -226,7 +226,7 @@ public class ProductionService {
                 String oldSummary = text.substring(oldStart + oldSummaryMarker.length(), newStart).trim();
                 String newSummary = text.substring(newStart + newSummaryMarker.length()).trim();
 
-                System.out.println("Saving summaries for video " + videoId);
+                log.info("Saving summaries for video {}", videoId);
                 
                 script.setOldScriptSummary(oldSummary);
                 script.setNewScriptSummary(newSummary);
@@ -270,7 +270,7 @@ public class ProductionService {
             // 1. Fetch content using API
             String text = readGoogleDoc(docId);
             
-            System.out.println("Saving final script for video " + videoId);
+            log.info("Saving final script for video {}", videoId);
             
             // 2. Save to DB
             script.setFinalScript(text);
@@ -307,7 +307,7 @@ public class ProductionService {
             // 1. Fetch content using API
             String text = readGoogleDoc(docId);
             
-            System.out.println("Saving opening script for video " + videoId);
+            log.info("Saving opening script for video {}", videoId);
             
             // 2. Save to DB
             script.setOpeningScript(text);

src/main/java/com/hlab/yanalyst/global/config/RestTemplateConfig.java

@@ -21,4 +21,17 @@ public class RestTemplateConfig {
                 })
                 .build();
     }
+
+    /**
+     * Python 마이크로서비스(Whisper 전사 /transcribe, ffmpeg 렌더 /render)용 RestTemplate.
+     * 전사·인코딩은 수십 초~수 분이 걸릴 수 있어 read timeout 을 길게 둔다.
+     * (주입 시 빈 이름 {@code pythonRestTemplate} 로 구분 — 다른 곳의 restTemplate 주입에는 영향 없음)
+     */
+    @Bean
+    public RestTemplate pythonRestTemplate(RestTemplateBuilder builder) {
+        return builder
+                .connectTimeout(Duration.ofSeconds(20))
+                .readTimeout(Duration.ofMinutes(10))
+                .build();
+    }
 }