docs: simplify documentation - clarify two separate systems

Rewrite documentation to clearly separate the two systems:

README.md Changes:
- Restructure as two independent systems (NotebookLM Agent vs DocuMente)
- Clear separation of requirements:
  * NotebookLM Agent: NO Qdrant needed
  * DocuMente RAG: Qdrant REQUIRED
- Remove confusing 'dual-system' language
- Add FAQ section clarifying common questions
- Simplified examples for each system
- Clear statement: systems work independently

docs/integration.md Changes:
- Remove overly complex architecture diagrams
- Focus on practical usage only
- Simplified to 3 steps: start services → sync → query
- Remove redundant API documentation (refer to SKILL.md)
- Add clear use cases section
- Shorter troubleshooting section

docs/README.md Changes:
- Minimal structure overview
- Clear separation of endpoints by system
- Quick links to relevant docs

Impact:
- 821 lines removed, 259 added
- Much clearer for new users
- No confusion about Qdrant requirements
- Clear distinction between the two systems

Closes documentation clarity issue

docs/README.md

@@ -1,71 +1,55 @@
-# Documentation
+# Documentazione
 
-Benvenuto nella documentazione di NotebookLM Agent API.
+## Struttura
 
-## Indice
+```
+docs/
+├── README.md          # Questo file - panoramica
+├── integration.md     # Come usare NotebookLM con RAG
+└── api/              # Documentazione API dettagliata
+```
 
-- [API Reference](./api/) - Documentazione completa delle API (TODO)
-- [Examples](./examples/) - Esempi di utilizzo (TODO)
+## Guide Rapide
 
-## Panoramica
+### Solo NotebookLM Agent
+Non serve Qdrant. Vedi [README principale](../README.md) sezione "NotebookLM Agent".
 
-NotebookLM Agent API fornisce:
+### NotebookLM + RAG
+Serve Qdrant. Vedi [integration.md](./integration.md).
 
-1. **REST API** per gestire notebook, fonti, chat e generazione contenuti
-2. **Webhook System** per notifiche event-driven
-3. **AI Skill** per integrazione con agenti AI
+### API Reference
+Endpoint dettagliati in [api/endpoints.md](./api/endpoints.md).
+
+---
 
 ## Endpoint Principali
 
-### Notebook Management
-- `POST /api/v1/notebooks` - Creare notebook
-- `GET /api/v1/notebooks` - Listare notebook
-- `GET /api/v1/notebooks/{id}` - Ottenere notebook
-- `DELETE /api/v1/notebooks/{id}` - Eliminare notebook
+### NotebookLM Agent
+```
+POST   /api/v1/notebooks              # Crea notebook
+GET    /api/v1/notebooks              # Lista notebook
+POST   /api/v1/notebooks/{id}/sources # Aggiungi fonte
+POST   /api/v1/notebooks/{id}/chat    # Chat
+POST   /api/v1/webhooks               # Registra webhook
+```
 
-### Source Management
-- `POST /api/v1/notebooks/{id}/sources` - Aggiungere fonte
-- `GET /api/v1/notebooks/{id}/sources` - Listare fonti
-- `POST /api/v1/notebooks/{id}/sources/research` - Ricerca web
+### DocuMente RAG
+```
+POST   /api/v1/documents               # Upload documento
+POST   /api/v1/query                  # Query RAG
+POST   /api/v1/notebooklm/sync/{id}   # Sincronizza notebook
+GET    /api/v1/notebooklm/indexed     # Lista sincronizzati
+```
 
-### Content Generation
-- `POST /api/v1/notebooks/{id}/generate/audio` - Generare podcast
-- `POST /api/v1/notebooks/{id}/generate/video` - Generare video
-- `POST /api/v1/notebooks/{id}/generate/quiz` - Generare quiz
-- `POST /api/v1/notebooks/{id}/generate/flashcards` - Generare flashcard
-
-### Webhooks
-- `POST /api/v1/webhooks` - Registrare webhook
-- `GET /api/v1/webhooks` - Listare webhook
-- `POST /api/v1/webhooks/{id}/test` - Testare webhook
+---
 
 ## Autenticazione
 
-Tutte le richieste API richiedono header `X-API-Key`:
-
-```bash
-curl http://localhost:8000/api/v1/notebooks \
-  -H "X-API-Key: your-api-key"
+Header richiesto:
+```
+X-API-Key: your-api-key
 ```
 
-## Webhook Security
+---
 
-I webhook includono firma HMAC-SHA256 nell'header `X-Webhook-Signature`:
-
-```python
-import hmac
-import hashlib
-
-signature = hmac.new(
-    secret.encode(),
-    payload.encode(),
-    hashlib.sha256
-).hexdigest()
-```
-
-## Risorse
-
-- [README](../README.md) - Panoramica progetto
-- [PRD](../prd.md) - Requisiti prodotto
-- [SKILL.md](../SKILL.md) - Skill per agenti AI
-- [CONTRIBUTING](../CONTRIBUTING.md) - Come contribuire
+Per informazioni complete vedi [SKILL.md](../SKILL.md)