Add web interface and Docker deployment

Expose the paste tool through a lightweight web UI/API and provide the container setup required for the publicpaste service.

Dockerfile

@@ -0,0 +1,15 @@
+FROM python:3.12-slim
+
+ENV PYTHONDONTWRITEBYTECODE=1 \
+    PYTHONUNBUFFERED=1 \
+    PUBLICPASTE_HOST=0.0.0.0 \
+    PUBLICPASTE_PORT=12072 \
+    PUBLICPASTE_DATA_DIR=/data
+
+WORKDIR /app
+COPY . .
+RUN python -m pip install --no-cache-dir . \
+    && mkdir -p /data
+
+EXPOSE 12072
+CMD ["python", "-m", "publicpaste.web"]