* feat: add consent banner requirement for signers (B6)
- Add REQUIRE_CONSENT_KEY to AccountConfig for per-account toggle
- Add consent_given event type to SubmissionEvent for audit trail
- Add consent checkbox UI on last step of signing form (form.vue)
- Add isLastStep computed property and onConsentChange method
- Create API endpoint (submitter_consents#create) to record consent
- Add requireConsent prop passing from server via data attribute
- Add settings toggle in Account preferences page
- Add i18n translations for all 14 languages (JS + Rails)
- Submit button disabled until consent checkbox is checked
* fix: add REQUIRE_CONSENT_KEY to AccountConfigsController ALLOWED_KEYS
* fix: keep consent checkbox visible after checking (don't remove from DOM)
* fix: bind checkbox checked state to consentAccepted for step navigation sync
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Co-authored-by: mario.pander <developbob50@gmail.com>
devin-ai-integration[bot]