fix: make docker compose build and start the API

The image context was backend/, so COPY frontend/ failed. Build from the
repo root, place Python modules on the import path, and pin packages that
exist on PyPI. The web process no longer loads the LLM at startup.

backend/Dockerfile

@@ -2,32 +2,27 @@ FROM python:3.11-slim
 
 WORKDIR /app
 
-# Install system dependencies
-RUN apt-get update && apt-get install -y \
+RUN apt-get update && apt-get install -y --no-install-recommends \
     curl \
     && rm -rf /var/lib/apt/lists/*
 
-# Create directories
-RUN mkdir -p /app/uploads /app/index /app/models
+RUN mkdir -p /app/uploads /app/index /app/models /app/books
 
-# Copy requirements
-COPY requirements.txt .
-
-# Install Python dependencies
+COPY backend/requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt
 
-# Set environment variables
-ENV GPT4ALL_MODEL=llama-3.2-3b-instruct-q4_0.gguf
+ENV PYTHONPATH=/app
+ENV GPT4ALL_MODEL=/app/models/llama-3.2-3b-instruct-q4_0.gguf
 ENV UPLOAD_DIR=/app/uploads
+ENV BOOKS_DIR=/app/books
 ENV INDEX_DIR=/app/index
 ENV SCHEDULES_PATH=/app/schedules.json
 
-# Copy application
-COPY app/ ./app/
-COPY frontend/ ./frontend/
+COPY backend/app ./app
+COPY backend/templates ./templates
+COPY backend/scripts ./scripts
+COPY frontend ./frontend
 
-# Expose ports
 EXPOSE 8000
 
-# Run the application
 CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8000"]