Forecasting app: hybrid port to HNF stack

Python FastAPI ML backend kept intact; auth replaced with central hnf_session cookie verification. Frontend rebuilt on React 18 + TS + Vite with stack design system, Plotly charts retained. Shared Postgres via DATABASE_URL; schema applied on startup.

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

backend/Dockerfile

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+FROM python:3.11-slim
+
+WORKDIR /app
+
+RUN apt-get update && apt-get install -y \
+    build-essential \
+    libpq-dev \
+    postgresql-client \
+    g++ \
+    make \
+    curl \
+    && rm -rf /var/lib/apt/lists/*
+
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+# Playwright + Chromium for Booking.com scraper
+RUN playwright install chromium --with-deps
+
+# CmdStan for Prophet
+RUN python -m cmdstanpy.install_cmdstan --cores 2
+
+# Fix Prophet cmdstan path symlink
+RUN CMDSTAN_VERSION=$(ls /root/.cmdstan/ | head -1) && \
+    rm -rf /usr/local/lib/python3.11/site-packages/prophet/stan_model/cmdstan-* && \
+    ln -s /root/.cmdstan/$CMDSTAN_VERSION /usr/local/lib/python3.11/site-packages/prophet/stan_model/cmdstan-2.31.0
+
+COPY . .
+
+EXPOSE 8000
+
+CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000"]