Record client IP address

Provide and option in the form settings to record the submitter client's IP address (v4 or v6) as an implicit extra "answer", exportable as an extra column. It may or may not enable a

• Nextcloud-Version: any
• Forms-Version: any

Is your feature request related to a problem? Please describe.
It would facilitate filtering out spammy submissions when automatically processing the report, instead of having to dig into access logs. It would also allow some finer control when asking the user for their e-mail address.

Describe the solution you'd like

• Under "Form settings", add a checkbox: "Record client IP address."
• If the previous option is active, add a textbox: "Show warning: [ Your IP address will be recorded. ]" and publish it in the footer of the form.
• When exporting as a spreadsheet/CSV, add a column like "Client IP address" (or custom question id).

Describe alternatives you've considered

• Digging into access logs.
• Try to pattern-match the answers.
• Asking the user to manually fill-in their IP address.

Additional context

• Consider both IPv4 and IPv6.

No files or tests are named. Start by locating the form settings UI, submission handling, and spreadsheet/CSV export paths, then trace how an optional implicit answer could flow through them. Done means an opt-in IPv4/IPv6 client IP, optional warning text in the form footer, and an export column are covered by appropriate tests.