LOOPIN-020 — Add AI moderation integration layer

[shaig-mahmudov]

• Type: Backend
• Priority: Optional / Medium
• Branch: feature/LOOPIN-020-ai-moderation-integration
• Description: Create a modular service interface for checking risky text using AI fallbacks.
• Acceptance Criteria:
  • Interface allows AI checking after manual validation.
  • App continues working if the AI API fails.
  • Configured via environment variables without hardcoded keys.