Add Reddit monitoring bot — backend, frontend, and Docker config

Python/FastAPI backend with PostgreSQL for collecting Reddit data via
public .json endpoints. React/Vite dashboard for analytics. Docker Compose
setup with API and worker services connecting to shared PostgreSQL.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Dockerfile.worker

@@ -0,0 +1,11 @@
+FROM python:3.12-slim
+WORKDIR /app
+
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+COPY backend/ backend/
+COPY alembic/ alembic/
+COPY alembic.ini .
+
+CMD ["python", "-m", "backend.worker.main"]