feat: BIND DNS Web Manager - Web interface for managing BIND9 DNS server

- Flask + SQLite web app with user authentication
- Zone management: create/delete zones, edit raw zone files
- Record management: add/delete A/AAAA/CNAME/MX/TXT/NS/PTR/SRV/CAA records
- Service control: start/stop/restart/reload BIND via systemctl/rndc
- Configuration editor: edit named.conf.options/local with syntax validation
- DNS query testing: online dig tool
- Audit log: all operations logged with user/timestamp
- BIND9 backend, listening on port 53

templates/zone_raw.html

@@ -0,0 +1,45 @@
+{% extends "base.html" %}
+{% block title %}{{ zone.name }} 原始文件 - DNS{% endblock %}
+{% block content %}
+<div class="page-header">
+    <div>
+        <h1>原始 Zone 文件: {{ zone.name }}</h1>
+        <p class="text-muted text-sm">文件: {{ zone.file }}</p>
+    </div>
+    <a href="{{ url_for('zone_detail', zone_name=zone.name) }}" class="btn btn-secondary">← 返回</a>
+</div>
+
+<div class="card">
+    <div class="card-body">
+        <form method="POST">
+            <div class="form-group">
+                <textarea name="content" class="code-editor" rows="25" spellcheck="false">{{ content }}</textarea>
+            </div>
+            <div class="form-actions">
+                <button type="submit" class="btn btn-primary">💾 保存并重载</button>
+                <a href="{{ url_for('zone_detail', zone_name=zone.name) }}" class="btn btn-secondary">取消</a>
+            </div>
+        </form>
+    </div>
+</div>
+
+<div class="card">
+    <div class="card-header"><h2>格式说明</h2></div>
+    <div class="card-body">
+        <pre class="text-sm text-muted">
+$TTL 86400                    ; 默认 TTL
+@   IN  SOA ns1.example.com. admin.example.com. (
+        2026070901  ; Serial  - 每次修改需递增
+        3600        ; Refresh - 从服务器刷新间隔
+        900         ; Retry   - 刷新失败重试间隔
+        604800      ; Expire  - 过期时间
+        86400       ; Minimum - 否定缓存TTL
+        )
+@   IN  NS  ns1.example.com.   ; NS 记录
+www IN  A   192.168.1.100      ; A 记录
+mail IN A   192.168.1.200      ; A 记录
+@   IN  MX  10 mail.example.com. ; MX 记录
+        </pre>
+    </div>
+</div>
+{% endblock %}