feat(test): add Phase 5b integration and E2E tests

Add comprehensive integration and end-to-end test suites:
- Integration tests for API flows (authorization, token, verification)
- Integration tests for middleware chain and security headers
- Integration tests for domain verification services
- E2E tests for complete authentication flows
- E2E tests for error scenarios and edge cases
- Shared test fixtures and utilities in conftest.py
- Rename Dockerfile to Containerfile for Podman compatibility

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Containerfile

@@ -0,0 +1,88 @@
+# Gondulf IndieAuth Server - OCI-Compliant Containerfile/Dockerfile
+# Compatible with both Podman and Docker
+# Optimized for rootless Podman deployment
+
+# Build stage - includes test dependencies
+FROM python:3.12-slim-bookworm AS builder
+
+# Install uv package manager (must match version used to create uv.lock)
+RUN pip install --no-cache-dir uv==0.9.8
+
+# Set working directory
+WORKDIR /app
+
+# Copy dependency files and README (required by hatchling build)
+COPY pyproject.toml uv.lock README.md ./
+
+# Install all dependencies including test dependencies
+RUN uv sync --frozen --extra test
+
+# Copy source code and tests
+COPY src/ ./src/
+COPY tests/ ./tests/
+
+# Run tests (fail build if tests fail)
+RUN uv run pytest tests/ --tb=short -v
+
+# Production runtime stage
+FROM python:3.12-slim-bookworm
+
+# Copy a marker file from builder to ensure tests ran
+# This creates a dependency on the builder stage so it cannot be skipped
+COPY --from=builder /app/pyproject.toml /tmp/build-marker
+RUN rm /tmp/build-marker
+
+# Create non-root user with UID 1000 (compatible with rootless Podman)
+RUN groupadd -r -g 1000 gondulf && \
+    useradd -r -u 1000 -g gondulf -m -d /home/gondulf gondulf
+
+# Install runtime dependencies
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends \
+        ca-certificates \
+        wget \
+        sqlite3 \
+    && rm -rf /var/lib/apt/lists/*
+
+# Set working directory
+WORKDIR /app
+
+# Install uv in runtime (needed for running the app)
+RUN pip install --no-cache-dir uv==0.9.8
+
+# Copy pyproject.toml, lock file, and README (required by hatchling build)
+COPY pyproject.toml uv.lock README.md ./
+
+# Install production dependencies only (no dev/test)
+RUN uv sync --frozen --no-dev
+
+# Copy application code from builder
+COPY --chown=gondulf:gondulf src/ ./src/
+
+# Copy entrypoint script
+COPY --chown=gondulf:gondulf deployment/docker/entrypoint.sh /entrypoint.sh
+RUN chmod +x /entrypoint.sh
+
+# Create directories for data and backups
+RUN mkdir -p /data /data/backups && \
+    chown -R gondulf:gondulf /data
+
+# Set environment variables
+ENV PATH="/app/.venv/bin:$PATH" \
+    PYTHONUNBUFFERED=1 \
+    PYTHONDONTWRITEBYTECODE=1 \
+    PYTHONPATH=/app/src
+
+# Expose port
+EXPOSE 8000
+
+# Health check using wget
+HEALTHCHECK --interval=30s --timeout=5s --start-period=10s --retries=3 \
+    CMD wget --no-verbose --tries=1 --spider http://localhost:8000/health || exit 1
+
+# Switch to non-root user
+USER gondulf
+
+# Set entrypoint and default command
+ENTRYPOINT ["/entrypoint.sh"]
+CMD ["uvicorn", "gondulf.main:app", "--host", "0.0.0.0", "--port", "8000"]