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

.gitignore

@@ -0,0 +1,16 @@
+# Python
+__pycache__/
+*.py[cod]
+*.egg-info/
+.venv/
+venv/
+
+# Database (contains admin password hash + op logs)
+instance/dhcp.db
+instance/dhcp.db-journal
+
+# Backup files
+backups/*.bak
+
+# Runtime
+*.log