fix: add ffmpeg to Dockerfile and update error message in entrypoint.sh to English

Dockerfile

@@ -25,7 +25,7 @@ RUN --mount=type=cache,target=/root/.cache/go-build \
 
 FROM alpine:latest
 
-RUN apk add --no-cache curl
+RUN apk add --no-cache curl ffmpeg
 
 WORKDIR /app
 

entrypoint.sh

@@ -11,7 +11,7 @@ if [ -n "$CONFIG_URL" ]; then
 fi
 
 if [ ! -f /app/config.toml ]; then
-    echo "[ERROR] Missing config.toml: 请通过挂载或 CONFIG_URL 提供配置文件"
+    echo "[ERROR] Missing config.toml: Please provide the configuration file via mounting or CONFIG_URL"
     exit 1
 fi