v0.281.0: 'Done' asks the probe first; sign-up closed after the first admin (decision 47); R-713 code-bound values refused, ${NAME|base64}

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS

controller/internal/web/templates/signupclosed.html

@@ -0,0 +1,23 @@
+{{define "signupclosed"}}
+<!DOCTYPE html>
+<html lang="{{T "layout.html_lang"}}">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <meta name="robots" content="noindex">
+    <title>{{if .AppName}}{{.AppName}} — {{end}}{{T "signup_closed.page_title"}}</title>
+    <link rel="stylesheet" href="/static/style.css?v={{.Version}}">
+</head>
+<body class="login-body">
+    <div class="login-card">
+        <img src="/static/felhom-logo.svg?v={{.Version}}" alt="Felhom.eu" class="login-logo">
+        {{- if .AppName}}
+        <h1 class="login-title">{{.AppName}}</h1>
+        {{- end}}
+        <p id="signup-closed-text">{{T "signup_closed.page_body"}}</p>
+        <p class="login-footer">{{.Host}}</p>
+        <div class="shell-lang">{{template "lang_globe" .}}</div>
+    </div>
+</body>
+</html>
+{{end}}