add docker file

InConstruction/Dockerfile

@@ -0,0 +1,27 @@
+# Slim Python image
+FROM python:3.12-slim
+
+ENV PYTHONDONTWRITEBYTECODE=1 \
+    PYTHONUNBUFFERED=1
+
+# System deps for pip & curl (for healthcheck)
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    build-essential curl \
+    && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /app
+
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+COPY . .
+
+# Default port used by the app
+ENV FLET_PORT=8080
+
+EXPOSE 8080
+
+# Simple health endpoint is the root
+HEALTHCHECK --interval=30s --timeout=3s --retries=3 CMD curl -fsS http://127.0.0.1:8080/ || exit 1
+
+CMD ["python", "main.py"]