fix(ui): unify header/breadcrumb treatment, drop redundant back buttons

The page-top chrome was inconsistent: most nested views used the breadcrumb
kicker + page-title pattern, but plugin sub-pages used ad-hoc "← back" links,
~11 pages stacked a breadcrumb AND a redundant ancestor back button, and two
(monitors/edit, hosts/uptime) had a back button but no breadcrumb. The
settings/plugin_detail page stacked all of it at once.

Unify on the breadcrumb-led model:
- settings/_tabs.html: drop the hardcoded "Settings" h1; the breadcrumb
  ("Settings › …") plus the tab strip is the header.
- settings/plugin_detail: drop the "← Plugins" back button.
- docker container_detail/swarm/disk + snmp/device: replace ad-hoc back links
  with the standard crumbs() breadcrumb.
- host_agent, ansible/*, alerts/maintenance: remove redundant ancestor back
  buttons (the breadcrumb's parent crumbs already link there); keep lateral
  shortcuts (Inventory/Schedules/Browse/Targets/Groups/New).
- monitors/edit, hosts/uptime: add the missing breadcrumb, drop the back link.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016Jg27rgypiW2efULXJDtMC

steward/templates/ansible/browse.html

@@ -17,7 +17,6 @@
       {% endif %}
       <a href="/ansible/inventory/targets" class="btn btn-ghost btn-sm">Inventory</a>
       <a href="/ansible/schedules" class="btn btn-ghost btn-sm">Schedules</a>
-      <a href="/ansible/" class="btn btn-ghost btn-sm">← Run History</a>
     </div>
 </div>
 
@@ -35,7 +34,6 @@
                 <button type="submit" class="btn btn-sm btn-danger">Delete</button>
             </form>
             {% endif %}
-            <a href="/ansible/browse" class="btn btn-ghost btn-sm">← Back to browse</a>
         </div>
     </div>
     <pre style="background:var(--bg);padding:1rem;border-radius:4px;overflow-x:auto;font-size:0.8rem;color:var(--text-muted);max-height:600px;overflow-y:auto;">{{ view_contents }}</pre>

steward/templates/ansible/inventory/group_detail.html

@@ -5,7 +5,6 @@
 {% block content %}
 <div style="display:flex;align-items:center;justify-content:space-between;margin-bottom:1.5rem;">
     <h1 class="page-title" style="margin-bottom:0;">Group: {{ group.name }}</h1>
-    <a href="/ansible/inventory/groups" class="btn btn-ghost btn-sm">← Groups</a>
 </div>
 
 <form method="post" action="/ansible/inventory/groups/{{ group.id }}">

steward/templates/ansible/inventory/groups.html

@@ -7,7 +7,6 @@
     <h1 class="page-title" style="margin-bottom:0;">Inventory Groups</h1>
     <div style="display:flex;gap:0.5rem;">
         <a href="/ansible/inventory/targets" class="btn btn-ghost btn-sm">Targets</a>
-        <a href="/ansible/" class="btn btn-ghost btn-sm">← Ansible</a>
     </div>
 </div>
 

steward/templates/ansible/inventory/target_detail.html

@@ -5,7 +5,6 @@
 {% block content %}
 <div style="display:flex;align-items:center;justify-content:space-between;margin-bottom:1.5rem;">
     <h1 class="page-title" style="margin-bottom:0;">Target: {{ target.name }}</h1>
-    <a href="/ansible/inventory/targets" class="btn btn-ghost btn-sm">← Targets</a>
 </div>
 
 <form method="post" action="/ansible/inventory/targets/{{ target.id }}">

steward/templates/ansible/inventory/targets.html

@@ -7,7 +7,6 @@
     <h1 class="page-title" style="margin-bottom:0;">Inventory Targets</h1>
     <div style="display:flex;gap:0.5rem;">
         <a href="/ansible/inventory/groups" class="btn btn-ghost btn-sm">Groups</a>
-        <a href="/ansible/" class="btn btn-ghost btn-sm">← Ansible</a>
     </div>
 </div>
 

steward/templates/ansible/playbook_editor.html

@@ -5,7 +5,6 @@
 {% block content %}
 <div style="display:flex;align-items:center;justify-content:space-between;margin-bottom:1.25rem;gap:1rem;flex-wrap:wrap;">
   <h1 class="page-title" style="margin-bottom:0;">{{ "Edit playbook" if editing else "New playbook" }}</h1>
-  <a href="/ansible/browse" class="btn btn-ghost btn-sm">← Browse</a>
 </div>
 
 {% if error %}<div class="alert alert-error">{{ error }}</div>{% endif %}

steward/templates/ansible/run_detail.html

@@ -4,7 +4,6 @@
 {% block breadcrumb %}{{ crumbs([("Ansible", "/ansible/"), ("Run " ~ run.id[:8], "")]) }}{% endblock %}
 {% block content %}
 <div style="display:flex;align-items:center;gap:1rem;margin-bottom:1.5rem;">
-    <a href="/ansible/" class="btn btn-ghost btn-sm">← Runs</a>
     <h1 class="page-title" style="margin-bottom:0;">Run Detail</h1>
     <div style="margin-left:auto;display:flex;gap:0.5rem;">
         {% if run.status.value in ("running", "queued") and session.user_role in ("operator", "admin") %}

steward/templates/ansible/schedules.html

@@ -14,7 +14,6 @@
   <div style="display:flex;gap:0.5rem;">
     <a href="/ansible/inventory/targets" class="btn btn-ghost">Inventory</a>
     <a href="/ansible/browse" class="btn btn-ghost">Browse</a>
-    <a href="/ansible/" class="btn btn-ghost">← Runs</a>
   </div>
 </div>