Initial commit: DHCP Web Manager

Flask-based web UI for managing ISC DHCP server (dhcpd).

Features:
- subnet / static host binding CRUD via web
- listen interface configuration (INTERFACESv4)
- active lease query + pool utilization stats
- service status, reload/restart, syntax check
- user auth + operation logs
- automatic backup before each config change
- safe change pipeline: write file → dhcpd -t → systemctl restart + is-active verify
- error messages include journalctl tail for diagnosis

templates/logs.html

@@ -0,0 +1,47 @@
+{% extends "base.html" %}
+{% block title %}操作日志{% endblock %}
+{% block content %}
+<div class="page-head">
+    <h1>操作日志</h1>
+    <span class="muted">共 {{ total }} 条</span>
+</div>
+
+<table class="data-table">
+    <thead>
+        <tr>
+            <th>时间</th>
+            <th>用户</th>
+            <th>操作</th>
+            <th>对象</th>
+            <th>结果</th>
+            <th>消息</th>
+        </tr>
+    </thead>
+    <tbody>
+    {% for l in logs %}
+    <tr>
+        <td><span class="small">{{ l.timestamp.strftime('%Y-%m-%d %H:%M:%S') }}</span></td>
+        <td>{{ l.user }}</td>
+        <td><code>{{ l.action }}</code></td>
+        <td><code>{{ l.target }}</code></td>
+        <td>
+            {% if l.result == 'ok' %}
+                <span class="badge badge-ok">{{ l.result }}</span>
+            {% else %}
+                <span class="badge badge-warn">{{ l.result }}</span>
+            {% endif %}
+        </td>
+        <td><span class="small">{{ l.message }}</span></td>
+    </tr>
+    {% endfor %}
+    </tbody>
+</table>
+
+{% if pages > 1 %}
+<div class="pager">
+    {% if page > 1 %}<a href="?page={{ page-1 }}" class="btn">← 上一页</a>{% endif %}
+    <span class="muted">第 {{ page }} / {{ pages }} 页</span>
+    {% if page < pages %}<a href="?page={{ page+1 }}" class="btn">下一页 →</a>{% endif %}
+</div>
+{% endif %}
+{% endblock %}