Refactor web build process and update documentation

- Removed Node.js build artifacts from .gitignore and adjusted Makefile to reflect changes in web UI build process, now using server-rendered Go templates instead of React.
- Updated README to clarify the new web UI architecture and output formats, emphasizing the removal of the Node.js build step.
- Added a command to set the number of frames per render task in manager configuration, enhancing user control over rendering settings.
- Improved Gitea workflow by removing unnecessary npm install step, streamlining the CI process.

web/templates/partials/admin_runners.html

@@ -0,0 +1,35 @@
+{{ define "partial_admin_runners" }}
+{{ $runners := index . "runners" }}
+{{ if not $runners }}
+<p>No runners registered.</p>
+{{ else }}
+<table class="table">
+  <thead>
+    <tr>
+      <th>ID</th>
+      <th>Name</th>
+      <th>Host</th>
+      <th>Status</th>
+      <th>Priority</th>
+      <th>Heartbeat</th>
+      <th>Actions</th>
+    </tr>
+  </thead>
+  <tbody>
+  {{ range $runner := $runners }}
+    <tr>
+      <td>{{ $runner.ID }}</td>
+      <td>{{ $runner.Name }}</td>
+      <td>{{ $runner.Hostname }}</td>
+      <td><span class="status {{ statusClass $runner.Status }}">{{ $runner.Status }}</span></td>
+      <td>{{ $runner.Priority }}</td>
+      <td>{{ formatTime $runner.LastHeartbeat }}</td>
+      <td class="row">
+        <button class="btn tiny danger" data-delete-runner="{{ $runner.ID }}">Delete</button>
+      </td>
+    </tr>
+  {{ end }}
+  </tbody>
+</table>
+{{ end }}
+{{ end }}