feat(master): htmx UI with live service overview and agent management

Vendored static assets (sha256):
e209dda5c8235479f3166defc7750e1dbcd5a5c1808b7792fc2e6733768fb447  htmx.min.js (htmx.org@2.0.4)
83eca6fa0611fe2b0bf1700b424b88b5eced38ef448ef9760a2ea08fbc875611  htmx-ext-sse.js (htmx-ext-sse@2.2.2)

internal/master/web/templates/overview.html

@@ -0,0 +1,29 @@
+{{define "content"}}
+<h1>Services</h1>
+<div id="services" hx-get="/fragments/services" hx-trigger="sse:services" hx-swap="innerHTML">
+  {{template "services" .}}
+</div>
+{{end}}
+
+{{define "services"}}
+{{range .Groups}}
+<section>
+  <h2>{{.Title}}</h2>
+  <table>
+    <thead><tr><th>Service</th><th>Image</th><th>Status</th><th>Mode</th></tr></thead>
+    <tbody>
+    {{range .Services}}
+      <tr>
+        <td>{{.DisplayName}}{{if .Self}} <span class="badge">managed outside</span>{{end}}</td>
+        <td><code>{{shortRef .ActualRef}}</code></td>
+        <td class="status status-{{.Status}}">{{.Status}}</td>
+        <td>{{.UpdateMode}}</td>
+      </tr>
+    {{end}}
+    </tbody>
+  </table>
+</section>
+{{else}}
+<p>No services reported yet. <a href="/agents">Add an agent</a> to get started.</p>
+{{end}}
+{{end}}