Add server control (start/stop/restart, live logs, broadcast, kick) to webadmin

Docker SDK drives login/char/worldserver containers via docker.sock (mounted
read-only into webadmin); live logs stream over SSE with nginx buffering
disabled so lines arrive in real time. Broadcast/kick go through a new
admin_queue DB table that the world server polls every ~2s in its existing
WorldProcess tick loop, avoiding a second IPC channel to the game server.

webadmin/templates/server.html

@@ -0,0 +1,103 @@
+{% extends "base.html" %}
+{% block title %}Server – ROSS Admin{% endblock %}
+{% block content %}
+<h2>Serversteuerung</h2>
+
+<div class="card">
+  <table>
+    <thead><tr><th>Dienst</th><th>Status</th><th>Gestartet</th><th></th></tr></thead>
+    <tbody>
+      {% for service in services %}
+      <tr>
+        <td>{{ service }}</td>
+        <td>
+          {% set st = statuses[service]['status'] %}
+          <span class="badge {{ 'ok' if st == 'running' else 'off' }}">{{ st }}</span>
+        </td>
+        <td>{{ statuses[service]['started_at'] or '-' }}</td>
+        <td class="row-actions">
+          <form class="inline" method="post" action="{{ url_for('server_action', service=service, action='start') }}">
+            <button type="submit">Start</button>
+          </form>
+          <form class="inline" method="post" action="{{ url_for('server_action', service=service, action='restart') }}">
+            <button type="submit" class="secondary">Restart</button>
+          </form>
+          <form class="inline" method="post" action="{{ url_for('server_action', service=service, action='stop') }}"
+                onsubmit="return confirm('{{ service }} wirklich stoppen?');">
+            <button type="submit" class="secondary" style="background:var(--danger)">Stop</button>
+          </form>
+        </td>
+      </tr>
+      {% endfor %}
+    </tbody>
+  </table>
+</div>
+
+<div class="card">
+  <h3 style="margin-top:0">Live-Logs</h3>
+  <div class="service-tabs">
+    {% for service in services %}
+    <button type="button" class="tab {{ 'active' if loop.first else '' }}" data-service="{{ service }}" onclick="switchLog('{{ service }}')">{{ service }}</button>
+    {% endfor %}
+  </div>
+  <div id="logbox" class="logbox"></div>
+</div>
+
+<div class="grid">
+  <div class="card">
+    <h3 style="margin-top:0">Broadcast</h3>
+    <form method="post" action="{{ url_for('server_broadcast') }}">
+      <label>Nachricht an alle Spieler</label>
+      <input type="text" name="message" maxlength="250" required>
+      <div style="margin-top:12px"><button type="submit">Senden</button></div>
+    </form>
+  </div>
+
+  <div class="card">
+    <h3 style="margin-top:0">Online-Spieler</h3>
+    {% if online %}
+    <table>
+      <thead><tr><th>Account</th><th>Charakter</th><th></th></tr></thead>
+      <tbody>
+        {% for row in online %}
+        <tr>
+          <td>{{ row['username'] }}</td>
+          <td>{{ row['lastchar'] }}</td>
+          <td class="row-actions">
+            <form class="inline" method="post" action="{{ url_for('server_kick') }}"
+                  onsubmit="return confirm('{{ row['lastchar'] }} kicken?');">
+              <input type="hidden" name="charname" value="{{ row['lastchar'] }}">
+              <button type="submit" class="secondary" style="background:var(--danger)">Kick</button>
+            </form>
+          </td>
+        </tr>
+        {% endfor %}
+      </tbody>
+    </table>
+    {% else %}
+    <p style="color:var(--muted)">Niemand online.</p>
+    {% endif %}
+  </div>
+</div>
+
+<script>
+let currentSource = null;
+function switchLog(service) {
+  document.querySelectorAll('.service-tabs .tab').forEach(function(btn) {
+    btn.classList.toggle('active', btn.dataset.service === service);
+  });
+  const box = document.getElementById('logbox');
+  box.textContent = '';
+  if (currentSource) currentSource.close();
+  currentSource = new EventSource('{{ url_for("server_logs", service="__SERVICE__") }}'.replace('__SERVICE__', service));
+  currentSource.onmessage = function(ev) {
+    const line = JSON.parse(ev.data);
+    const atBottom = box.scrollHeight - box.scrollTop - box.clientHeight < 40;
+    box.textContent += line + '\n';
+    if (atBottom) box.scrollTop = box.scrollHeight;
+  };
+}
+switchLog('{{ services[0] }}');
+window.addEventListener('beforeunload', function() { if (currentSource) currentSource.close(); });
+</script>
+{% endblock %}