feat: publish standalone worker

Separate worker packaging and service lifecycle from the control plane.

internal/webapp/templates/app_detail.html

@@ -0,0 +1,20 @@
+{{define "body"}}<section class="card">
+  <h1>{{.App.Name}}</h1>
+  <dl>
+    <dt>Source</dt><dd>{{.App.Source}}</dd>
+    <dt>PID</dt><dd>{{.App.PID}}</dd>
+    <dt>Open ports</dt>
+    <dd>
+      {{if .App.Ports}}
+        <ul>
+          {{range .App.Ports}}<li>{{.}}</li>{{end}}
+        </ul>
+      {{else}}<span class="muted">none</span>{{end}}
+    </dd>
+    <dt>Cmdline</dt><dd><code>{{.App.Cmdline}}</code></dd>
+    <dt>Cwd</dt><dd><code>{{.App.CWD}}</code></dd>
+    <dt>Last seen</dt><dd>{{fmtTime .App.LastSeen}}</dd>
+    <dt>Last check</dt><dd>— <span class="muted">(Phase 1: no per-app probes)</span></dd>
+  </dl>
+  <p><a href="/apps">← All apps</a></p>
+</section>{{end}}