v4.6.0-beta.1 — go2rtc customization

4.6.0

go2rtc customization — three long-standing issues that all
wanted a piece of the same knob: give the operator control over
go2rtc's ports, its API auth, and the stream set it serves.

• Basic auth on go2rtc's /api/* (#123):
  set GO2RTC_API_USERNAME + GO2RTC_API_PASSWORD and the
  bridge configures go2rtc's api.username/password, forwards
  Basic auth on every internal API call, and proxies the same
  credentials through the WebUI's HLS + WebSocket paths so
  browsers don't see a login prompt.
• Port overrides (#108):
  GO2RTC_API_PORT / GO2RTC_RTSP_PORT / GO2RTC_WEBRTC_PORT
  move go2rtc off :1984 / :8554 / :8889 when something
  else on the host wants them (e.g. Frigate on :1984).
• Extra streams pass-through (#106):
  GO2RTC_EXTRA_STREAMS=name=source[,name=source] registers
  additional streams alongside the Wyze cameras — RTSP, ONVIF,
  ffmpeg:, anything go2rtc understands. Camera names always
  win on collision.
• Verbatim YAML escape hatch: GO2RTC_EXTRA_YAML is appended
  to the managed config after a visible marker for anything the
  typed knobs above don't cover (custom publish: / hass: /
  ONVIF discovery blocks, etc.).
• HA add-on: new go2rtc options section wraps the same
  surface — api_port, api_username, api_password,
  rtsp_port, webrtc_port, extra_streams, extra_yaml.

Internal WebUI URL generation (RTSP-copy button, WebRTC copy) now
uses the configured ports instead of hard-coded 8554 / 1984.