fix: dockerfile librairies

Dockerfile

@@ -15,9 +15,15 @@ RUN pip install --no-cache-dir \
     torch torchaudio --index-url https://download.pytorch.org/whl/cpu
 
 # ── Python: audiocraft + flask ────────────────────────────────────────────────
-RUN pip install --no-cache-dir audiocraft flask
-
-# ── App code ──────────────────────────────────────────────────────────────────
+RUN apt-get update && apt-get install -y \
+    pkg-config \
+    libavformat-dev \
+    libavcodec-dev \
+    libswscale-dev \
+    && pip install --upgrade pip \
+    && pip install --no-cache-dir audiocraft flask
+
+    # ── App code ──────────────────────────────────────────────────────────────────
 COPY app.py index.html ./
 
 # ── Model cache directory (matches the Render persistent disk mount path) ─────