v0.3.3

Changes since v0.3.2

• u3_service: restore WLAN LED off at boot for red LED indicator
• bb400_gateway: add CLAUDE.md, fix .env migration for HTTP API password
• bb400_gateway: use separate credentials for MQTT and HTTP API
• bb400_gateway: set HTTP API auth to generated credentials
• bb400_gateway: add NanoMQ MQTT broker installer
• install: extract shared install logic into install_common.sh
• mqtt_viewer: multi-camera, stats overlay, diff graph
• docs: update README and CLAUDE.md for install_common.sh refactor