feat: #3636853 Provide a CAPTCHA integration point for (anonymous) flagging and unflagging

Julian Pustkuchenrequested to merge
issue/flag-3636853:3636853-provide-a-captcha-integration into 5.2.x
  • Per-flag form IDs for the confirm forms (flag_confirm_form_FLAG, unflag_confirm_form_FLAG, unflagging_form_FLAG), keeping the previous IDs as base form IDs.
  • New flag.challenge service deciding whether a flag action requires a challenge, with CAPTCHA point support and hook_flag_challenge_required_alter().
  • Normal and AJAX links send challenged users to the confirm form; AJAX links open it in a modal.
  • Direct action routes redirect challenged users to the confirm form instead of flagging.
  • AJAX confirm form submissions with validation errors keep the dialog open.

Co-Authored-By: Claude Opus 5.5 noreply@anthropic.com

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