Add Nmap output format compatibility (XML/grepable)

[stabrea]

Summary

Support exporting scan results in Nmap-compatible XML and grepable output formats for interoperability with existing security toolchains.

Motivation

• Many security tools (Metasploit, Nessus, OpenVAS) import Nmap XML format
• Grepable output (-oG) is widely used in scripting and automation pipelines
• Standards-based output makes the toolkit a drop-in complement to existing workflows
• Enables integration with vulnerability scanners and SIEM platforms

Proposed Approach

1. Nmap XML output (-oX equivalent):

   • Follow Nmap DTD schema for scan results
   • Include host, port, service, and state information
   • Add scan metadata (start time, arguments, scanner version)
   • Validate output against Nmap's DTD

2. Grepable output (-oG equivalent):

   • One host per line with tab-separated fields
   • Compatible with standard grep/awk processing
   • Include open/closed/filtered port states

3. JSON output (native):

   • Structured JSON for programmatic consumption
   • Nested host > port > service hierarchy

4. CLI integration:

   • -o xml, -o grep, -o json flags
   • -oA to output all formats simultaneously
   • Output to file or stdout

Acceptance Criteria

• XML output validates against Nmap DTD
• Grepable output parseable by common Nmap parsing scripts
• JSON output with complete scan information
• CLI flags for format selection and file output