ci: add multi-stage Dockerfile for containerized builds and testing

Author: EmbeddedOS CI

Dockerfile

@@ -0,0 +1,17 @@
+# ═══════════════════════════════════════════════════════════
+# Multi-stage Dockerfile — Python service
+# ═══════════════════════════════════════════════════════════
+FROM python:3.12-slim AS base
+WORKDIR /app
+COPY requirements*.txt ./
+RUN pip install --no-cache-dir -r requirements.txt 2>/dev/null || true
+COPY . .
+RUN pip install --no-cache-dir -e . 2>/dev/null || true
+
+FROM base AS test-runner
+RUN pip install --no-cache-dir pytest pytest-cov
+CMD ["python", "-m", "pytest", "tests/", "-v", "--tb=short"]
+
+FROM base AS production
+EXPOSE 8080
+CMD ["python", "-m", "uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8080"]