Initial commit: homelab dashboard

Elixir + Phoenix dashboard displaying public and internal homelab
services. Internal services are shown only when the request originates
from the local network, detected server-side via conn.remote_ip with
Traefik trusted as a proxy (RemoteIp plug).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

priv/static/robots.txt

@@ -0,0 +1,5 @@
+# See https://www.robotstxt.org/robotstxt.html for documentation on how to use the robots.txt file
+#
+# To ban all spiders from the entire site uncomment the next two lines:
+# User-agent: *
+# Disallow: /