fix: use CPU-only PyTorch and run init_db before alembic migrations

PyTorch default install pulls ~7GB of CUDA libs, exceeding disk on small
VMs. Switching to CPU-only saves ~6GB. Also run create_all before alembic
so migrations find existing tables on a fresh Postgres.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/Dockerfile

@@ -24,7 +24,11 @@ WORKDIR /app
 
 # Copy requirements first for better caching
 COPY requirements.txt .
-RUN pip install --no-cache-dir -r requirements.txt
+# Install PyTorch CPU-only FIRST so open-clip-torch doesn't pull the full
+# CUDA build (~7 GB).  CPU inference is all we need — the heavy lifting
+# happens through ONNX Runtime.
+RUN pip install --no-cache-dir torch torchvision --index-url https://download.pytorch.org/whl/cpu \
+    && pip install --no-cache-dir -r requirements.txt
 
 # Copy application code
 COPY . .

docker-compose.yml

@@ -38,7 +38,7 @@ services:
     # Run Alembic migrations before starting uvicorn. On a fresh Postgres
     # the empty 0001 baseline is a no-op stamp; create_all in init_db then
     # builds the schema.
-    command: sh -c "alembic upgrade head && uvicorn app.main:app --host 0.0.0.0 --port 8000 --reload"
+    command: sh -c "python -c \"import asyncio; from app.database import init_db; asyncio.run(init_db())\" && alembic upgrade head && uvicorn app.main:app --host 0.0.0.0 --port 8000 --reload"
     environment:
       - DATABASE_URL=postgresql+asyncpg://mulita:mulita@db:5432/mulita
       - REDIS_URL=redis://redis:6379