feat: add SoundFont inspection engine + AI instrument schema

- SoundFontInspector (sf2utils) scans .sf2, generates full/condensed catalog
- GET /api/v1/plugins/soundfonts/catalog with lazy init + cache invalidation
- AI tool generate_multitrack_midi now requires soundfont_id/bank/program
- Condensed catalog auto-injected into AI system prompt with bank rules
- Server render: FluidSynth program_select uses bank/program + channel routing (drums→ch9)
- VST3 pedalboard path inserts CC0 bank select + program change before notes
- DecentSamplerManager loads .dspreset with CWD fix for relative sample paths
- Pianobook render branch in render_engine.py
- Client SonicSF: controllerChange, programChange, applyAITrackInstrument
- Post-AI track creation applies instrument via applyAITrackInstrument
- Background cache rescan on .sf2 upload, frontend re-fetches catalog
- libcurl4 + VST3 dirs in Dockerfile

Dockerfile

@@ -19,18 +19,25 @@ RUN apt-get update && apt-get install -y \
     ffmpeg \
     libsndfile1 \
     libfluidsynth3 \
+    libcurl4 \
     build-essential \
     && rm -rf /var/lib/apt/lists/*
 
 # Thiết lập biến môi trường hiển thị cho X11 ảo
 ENV DISPLAY=:99
 
+# Create VST3 and sample directories
+RUN mkdir -p /opt/daw_engine/vst3 /opt/daw_engine/soundfonts /opt/daw_engine/samples/pianobook
+
 WORKDIR /app
 COPY requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt
 
 COPY . .
 
+# Copy VST3 plugins if present
+COPY ./vst_plugins/ /opt/daw_engine/vst3/
+
 # Tạo thư mục chứa file nhạc và cấp quyền ghi
 RUN mkdir -p /app/app/storage/uploads /app/app/storage/processed && chmod -R 777 /app/app/storage