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/hosts.html

@@ -0,0 +1,44 @@
+{% extends "base.html" %}
+{% block title %}静态绑定{% endblock %}
+{% block content %}
+<div class="page-head">
+    <h1>静态绑定（host 声明）</h1>
+    {% if is_admin %}<a href="{{ url_for('host_new') }}" class="btn btn-primary">+ 新增绑定</a>{% endif %}
+</div>
+
+{% if hosts %}
+<table class="data-table">
+    <thead>
+        <tr>
+            <th>主机名</th>
+            <th>MAC</th>
+            <th>固定 IP</th>
+            <th>操作</th>
+        </tr>
+    </thead>
+    <tbody>
+    {% for h in hosts %}
+    <tr>
+        <td><strong>{{ h.name }}</strong></td>
+        <td><code>{{ h.mac }}</code></td>
+        <td><code>{{ h.ip }}</code></td>
+        <td class="actions">
+            {% if is_admin %}
+            <a href="{{ url_for('host_edit', name=h.name) }}" class="btn btn-sm">编辑</a>
+            <form method="post" action="{{ url_for('host_delete', name=h.name) }}"
+                  onsubmit="return confirm('确认删除 host {{ h.name }}？');" style="display:inline">
+                <button type="submit" class="btn btn-sm btn-danger">删除</button>
+            </form>
+            {% else %}<span class="muted">—</span>{% endif %}
+        </td>
+    </tr>
+    {% endfor %}
+    </tbody>
+</table>
+{% else %}
+<div class="card empty">
+    <p>暂无静态绑定</p>
+    {% if is_admin %}<a href="{{ url_for('host_new') }}" class="btn btn-primary">+ 新增第一个</a>{% endif %}
+</div>
+{% endif %}
+{% endblock %}