Hub: accounts, IMVU linking by tagline, proxy sign-in, presence, console

People sign up on the website and link IMVU accounts by putting a code in the account's tagline, which the
hub reads from IMVU's public API (the most recent proof wins; link caps per person). IMVU's age verification
or Access Pass make an account adult. T5DE's proxy signs in with a device code and keeps a WebSocket open,
reporting the IMVU account in use and the community products it wears; /online shows those who opted in.
Moderators get a console: who's online, people, link caps, bans, roles, and the audit log. Tests run the
website and API against an embedded Postgres and a fake IMVU API.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

internal/web/templates/error.html

@@ -0,0 +1,8 @@
+{{define "title"}}Sorry{{end}}
+{{define "content"}}
+<div class="panel narrow">
+  <h1>Sorry</h1>
+  <p>{{.Message}}</p>
+  <div class="actions"><a class="button secondary" href="/">Home</a></div>
+</div>
+{{end}}