feat(deploy): merge Phase 5a deployment configuration

Complete containerized deployment system with Docker/Podman support.

Key features:
- Multi-stage Dockerfile with Python 3.11-slim base
- Docker Compose configurations for production and development
- Nginx reverse proxy with security headers and rate limiting
- Systemd service units for Docker, Podman, and docker-compose
- Backup/restore scripts with integrity verification
- Podman compatibility (ADR-009)

All tests pass including Podman verification testing.

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

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

docker-compose.yml

@@ -0,0 +1,53 @@
+version: '3.8'
+
+# Gondulf IndieAuth Server - Base Compose Configuration
+# Compatible with both podman-compose and docker-compose
+
+services:
+  gondulf:
+    build:
+      context: .
+      dockerfile: Dockerfile
+    image: gondulf:latest
+    container_name: gondulf
+    restart: unless-stopped
+
+    # Volume mounts
+    volumes:
+      - gondulf_data:/data
+      # Optional: Bind mount for backups (add :Z for SELinux with Podman)
+      # - ./backups:/data/backups:Z
+
+    # Environment variables (from .env file)
+    env_file:
+      - .env
+
+    # Port mapping (development/direct access)
+    # In production with nginx, remove this and use nginx reverse proxy
+    ports:
+      - "8000:8000"
+
+    # Health check (inherited from Dockerfile)
+    healthcheck:
+      test: ["CMD", "wget", "--no-verbose", "--tries=1", "--spider", "http://localhost:8000/health"]
+      interval: 30s
+      timeout: 5s
+      retries: 3
+      start_period: 10s
+
+    # Network
+    networks:
+      - gondulf_network
+
+volumes:
+  gondulf_data:
+    driver: local
+    # Optional: specify mount point on host with bind mount
+    # driver_opts:
+    #   type: none
+    #   device: /var/lib/gondulf/data
+    #   o: bind
+
+networks:
+  gondulf_network:
+    driver: bridge