v4.1.0 — Home Assistant ingress (show in sidebar)

✨ Show Nginx Proxy Manager in the Home Assistant sidebar

The add-on now supports Home Assistant ingress. Turn on "Show in
sidebar" on the add-on page and the interface opens inside Home Assistant.
That also works over HTTPS and remote access, with no extra port to open. The
admin port 81 keeps working exactly as before.

Upstream declined ingress support
(hassio-addons#649), so this is a fork-only feature.

How it works

• New patch 0004-Patch-support-Home-Assistant-ingress makes the Nginx
  Proxy Manager frontend base-path aware. It builds with a relative base and
  reads its path prefix at runtime from an ingress-path meta tag; the API
  client, the router and the image paths use it. On port 81 the prefix is
  empty, so nothing changes there.
• New rootfs/etc/nginx/conf.d/ingress.conf: an nginx server on the
  ingress port 8099 that only the Supervisor can reach. It serves the
  interface and fills in the meta tag from the X-Ingress-Path header. Port
  8099 is not exposed on the host.
• config.yaml: ingress: true, ingress_port: 8099,
  panel_icon: mdi:web. "Open Web UI" now opens the interface through ingress.

ℹ️ Good to know

• The sidebar and port 81 have separate logins. The interface keeps its
  login in the browser's per-site storage, and the sidebar runs under Home
  Assistant's address, so log in once in each.

✅ Verification

Built and tested on real aarch64 hardware running Home Assistant OS: the
interface opens from the sidebar, and port 81 keeps working.