fix: /simplify 리뷰 — UX/코드 품질 10건 수정

- EditableSegment: readOnly prop 추가, hover 배경색 효과
- MeetingDetailTabs: useMemo(parseSegments), 이중 debounce 제거, cleanup
- MeetingChatPanel: sessionId deps, 에러 표시, key=timestamp
- ExportMenu: i18n 위반 수정 (하드코딩 → t())
- MeetingModePage: 에러 Snackbar 피드백 (startRecording, viewDetail)
- TranscriptTab: polish 실패 피드백
- 12개 locale i18n 키 5개 추가

src/renderer/components/meeting/MeetingDetailTabs.tsx

@@ -1,7 +1,7 @@
 // src/renderer/components/meeting/MeetingDetailTabs.tsx
 // Phase 14.5: 풀스크린 탭 전환 컨테이너 — 전사 + 동적 문서 탭
 
-import { useState, useEffect, useCallback, useRef } from 'react'
+import { useState, useEffect, useCallback, useMemo } from 'react'
 import {
   Box,
   Tabs,
@@ -33,8 +33,6 @@ interface MeetingDetailTabsProps {
   onBack: () => void
 }
 
-const AUTOSAVE_DELAY = 500
-
 // 세그먼트 파싱: rawTranscript를 줄 단위로 분리
 function parseSegments(
   rawTranscript: string | null,
@@ -78,17 +76,19 @@ export function MeetingDetailTabs({
 }: MeetingDetailTabsProps): React.ReactElement {
   const { t } = useI18n()
   const [detail, setDetail] = useState<MeetingSessionDetail>(initialDetail)
-  const [documents, setDocuments] = useState<MeetingDocument[]>(initialDetail.documents ?? [])
+  const [documents, setDocuments] = useState<MeetingDocument[]>((initialDetail.documents ?? []).filter(Boolean))
   const [templates, setTemplates] = useState<MeetingDocTemplate[]>([])
   const [tabIndex, setTabIndex] = useState(0)
   const [dialogOpen, setDialogOpen] = useState(false)
   const [generating, setGenerating] = useState(false)
   const [editingTitle, setEditingTitle] = useState(false)
   const [titleDraft, setTitleDraft] = useState(detail.title ?? '')
-  const autoSaveTimers = useRef<Record<string, ReturnType<typeof setTimeout>>>({})
 
   // 세그먼트 파싱 (rawTranscript 기반)
-  const segments = parseSegments(detail.rawTranscript, detail.editedTranscript)
+  const segments = useMemo(
+    () => parseSegments(detail.rawTranscript, detail.editedTranscript),
+    [detail.rawTranscript, detail.editedTranscript],
+  )
 
   // 템플릿 로드
   useEffect(() => {
@@ -134,19 +134,16 @@ export function MeetingDetailTabs({
     [detail.id],
   )
 
-  // ── 문서 내용 자동저장 ──
+  // ── 문서 내용 자동저장 (DocumentTab 내부에 debounce 있음, 이중 래핑 제거) ──
   const handleDocContentChange = useCallback(
-    (docId: string, content: string) => {
-      if (autoSaveTimers.current[docId]) clearTimeout(autoSaveTimers.current[docId])
-      autoSaveTimers.current[docId] = setTimeout(async () => {
-        await window.electronAPI.meetingMode.updateDocument({
-          documentId: docId,
-          content,
-        })
-        setDocuments((prev) =>
-          prev.map((d) => (d.id === docId ? { ...d, content } : d)),
-        )
-      }, AUTOSAVE_DELAY)
+    async (docId: string, content: string) => {
+      await window.electronAPI.meetingMode.updateDocument({
+        documentId: docId,
+        content,
+      })
+      setDocuments((prev) =>
+        prev.map((d) => (d.id === docId ? { ...d, content } : d)),
+      )
     },
     [],
   )
@@ -286,8 +283,8 @@ export function MeetingDetailTabs({
           }}
         >
           <Tab label={t('meeting.transcriptTab')} />
-          {documents.map((doc) => (
-            <Tab key={doc.id} label={doc.title} />
+          {documents.filter(Boolean).map((doc) => (
+            <Tab key={doc.id} label={doc.title ?? t('meeting.untitled')} />
           ))}
           <Tab
             icon={<AddIcon sx={{ fontSize: 16 }} />}