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/device.html

@@ -0,0 +1,20 @@
+{{define "title"}}Sign T5DE in{{end}}
+{{define "content"}}
+<div class="panel narrow">
+  {{if .Approved}}
+  <h1>T5DE is signed in</h1>
+  <p class="muted">You can close this page and go back to T5DE.</p>
+  {{else}}
+  <h1>Sign T5DE in</h1>
+  <p class="muted">Enter the code T5DE shows, to sign it in as {{.Person.Username}}.</p>
+  {{if .Error}}<div class="error">{{.Error}}</div>{{end}}
+  <form method="post" action="/device">
+    <input type="hidden" name="csrf" value="{{.CSRF}}">
+    <label for="code">Code</label>
+    <input type="text" id="code" name="code" value="{{.Code}}" placeholder="XXXX-XXXX" required autofocus autocomplete="off">
+    <div class="actions"><button>Sign in</button></div>
+  </form>
+  <p class="muted small">Only enter a code you got from T5DE yourself.</p>
+  {{end}}
+</div>
+{{end}}