fix(chat-room): 접근성 라벨 및 다국어 문자열 적용

- 레이아웃 contentDescription 하드코딩 제거 및 strings 리소스화
- ChatMessageAdapter 접근성 문구를 리소스 기반으로 변환
- values-en 추가로 안내/버튼/접근성/상태 문구 영문화
- 타이핑 인디케이터 접근성 라벨 추가

app/src/main/res/values-en/strings.xml

@@ -0,0 +1,24 @@
+<resources>
+    <!-- Chat Room UI strings (English) -->
+    <string name="chat_notice_clone">AI Clone converses based on the creator\'s information, but it may not perfectly reflect all details or match real conversations.</string>
+    <string name="chat_notice_character">VoiceOn AI Character Talk allows a high degree of freedom. You can be anyone in the conversation. Talk as a character in a universe or create your own story with a new persona together with the character.\nNote: AI Character Talk is in open beta; conversations may be awkward or incomplete.</string>
+    <string name="chat_input_placeholder">Type a message</string>
+    <string name="action_send">Send</string>
+    <string name="action_retry">Retry</string>
+
+    <!-- Accessibility labels -->
+    <string name="a11y_profile_background">Profile background image</string>
+    <string name="a11y_back">Back</string>
+    <string name="a11y_profile_image">Profile image</string>
+    <string name="a11y_notice">Notice</string>
+    <string name="a11y_collapse">Collapse</string>
+    <string name="a11y_ai_profile_image">AI profile image</string>
+    <string name="a11y_typing">Typing…</string>
+
+    <!-- Accessibility phrases for adapter -->
+    <string name="a11y_my_message_prefix">My message</string>
+    <string name="a11y_message_word">Message</string>
+    <string name="status_sending">Sending</string>
+    <string name="status_failed">Failed to send</string>
+    <string name="status_sent">Sent</string>
+</resources>