feat: WhatsApp sales SaaS — "Genius" agent with free multi-provider brain

Multi-account WhatsApp sales & support agent (Baileys) for Hostting + Sahlaah.

- AI brain: Claude -> Groq -> Cerebras -> Gemini fallback chain (gpt-oss-120b
  free default), Egyptian-Arabic persona named "Genius", strict no-hallucination,
  Arabic-default language with English mirroring, 5s human-like "typing" delay.
- Knowledge: products/services + prices, business info & portfolio in persona;
  dashboard Products tab (CRUD) to manage the agent's knowledge.
- Inbox + modes OFF/SHADOW/COPILOT/AUTOPILOT; voice in (STT) + out (Egyptian TTS,
  emoji-stripped).
- Follow-up drip: 3 nudges in first 24h then twice-daily, each a different angle.
- Customers tab + human handoff: detects when a lead wants a person, flags them,
  bot backs off, owner takes over on WhatsApp (no phone numbers shared).
- Projects: auto-detect .com/.net client group chats, weekly re-scan.
- Campaigns (opt-in, throttled), Job queue + cron worker, contacts name sync.
- Resilience: unhandledRejection/uncaughtException handlers; provider 429/503 retry.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
