feat(api): implement notebook management CRUD endpoints

Implement Sprint 1: Notebook Management CRUD

- Add NotebookService with full CRUD operations
- Add POST /api/v1/notebooks (create notebook)
- Add GET /api/v1/notebooks (list with pagination)
- Add GET /api/v1/notebooks/{id} (get by ID)
- Add PATCH /api/v1/notebooks/{id} (partial update)
- Add DELETE /api/v1/notebooks/{id} (delete)
- Add Pydantic models for requests/responses
- Add custom exceptions (ValidationError, NotFoundError, NotebookLMError)
- Add comprehensive unit tests (31 tests, 97% coverage)
- Add API integration tests (26 tests)
- Fix router prefix duplication
- Fix JSON serialization in error responses

BREAKING CHANGE: None

.opencode/templates/githistory-entry.md

@@ -0,0 +1,30 @@
+# Git History Entry
+
+> Template per documentare commit con contesto completo.
+
+## YYYY-MM-DD HH:MM - type(scope): description
+
+**Hash:** `commit-hash`
+**Autore:** @agent
+**Branch:** branch-name
+
+### Contesto
+[Perché questo commit era necessario]
+
+### Cosa cambia
+[Descrizione modifiche]
+
+### Perché
+[Motivazione scelte]
+
+### Impatto
+- [ ] Nuova feature
+- [ ] Bug fix
+- [ ] Refactoring
+- [ ] Breaking change
+
+### File modificati
+- `file.py` - descrizione cambiamento
+
+### Note
+[Riferimenti issue, considerazioni]