refactor: consolidate to handler-base, migrate to pyproject.toml, add tests

Dockerfile

@@ -1,29 +1,9 @@
-FROM python:3.13-slim
+# Chat Handler - Using handler-base
+ARG BASE_TAG=latest
+FROM ghcr.io/billy-davies-2/handler-base:${BASE_TAG}
 
 WORKDIR /app
 
-# Install uv for fast, reliable package management
-COPY --from=ghcr.io/astral-sh/uv:latest /uv /usr/local/bin/uv
-
-# Install system dependencies
-RUN apt-get update && apt-get install -y --no-install-recommends \
-    curl \
-    && rm -rf /var/lib/apt/lists/*
-
-# Copy requirements first for better caching
-COPY requirements.txt .
-RUN uv pip install --system --no-cache -r requirements.txt
-
-# Copy application code
 COPY chat_handler.py .
 
-# Set environment variables
-ENV PYTHONUNBUFFERED=1
-ENV PYTHONDONTWRITEBYTECODE=1
-
-# Health check
-HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
-    CMD python -c "print('healthy')" || exit 1
-
-# Run the application
 CMD ["python", "chat_handler.py"]