Add tiled homepage; rename Business→Businesses; link footer copyright

- Home page (home.html) at / shows the sidebar sections as tiles; reachable by
  clicking the 'SimpleX Manager' brand in the sidebar (was redirecting to /users).
- Rename the category to 'Businesses' (route /businesses, tab/nav/_category),
  keeping the per-account bot_type 'business'. Fix profile back-link label.
- Footer: link 'Bournemouth Technology Ltd' -> bournemouthtechnology.co.uk and
  'SimpleX Network' -> simplex.chat.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

manager/templates/profile.html

@@ -29,7 +29,7 @@
 {% block content %}
 <div class="flex-between" style="margin-bottom: 20px;">
   <div class="flex gap-8">
-    <a href="{{ back }}" class="muted" style="text-decoration:none;">← {{ 'Users' if back == '/users' else 'Bots' }}</a>
+    <a href="{{ back }}" class="muted" style="text-decoration:none;">← {{ 'Users' if back == '/users' else ('Businesses' if back == '/businesses' else 'Bots') }}</a>
     <span class="muted">/</span>
     <strong>{{ profile.name }}</strong>
     <span class="tag {% if profile.bot_type == 'user' %}tag-user{% endif %}">{{ profile.bot_type }}</span>