feat(setup): T04 setup configuration files

- Create config.py with Pydantic Settings (SettingsConfigDict v2)
- Add all required configuration fields with defaults
- Create .env.example template with all environment variables
- Implement get_settings() with @lru_cache for performance
- Add test_configuration.py with 13 unit tests
- All tests passing (13/13)

Refs: T04

export/progress.md

@@ -9,11 +9,11 @@
 | Metrica | Valore |
 |---------|--------|
 | **Stato** | 🟡 In Progress |
-| **Progresso** | 4% |
+| **Progresso** | 5% |
 | **Data Inizio** | 2024-04-07 |
 | **Data Target** | TBD |
 | **Task Totali** | 74 |
-| **Task Completati** | 3 |
+| **Task Completati** | 4 |
 | **Task In Progress** | 1 |
 
 ---
@@ -37,11 +37,11 @@
 
 ## 📋 Task Pianificate
 
-### 🔧 Setup Progetto (T01-T05) - 3/5 completati
+### 🔧 Setup Progetto (T01-T05) - 4/5 completati
 - [x] T01: Creare struttura cartelle progetto (2024-04-07)
 - [x] T02: Inizializzare virtual environment e .gitignore (2024-04-07)
 - [x] T03: Creare requirements.txt con dipendenze (2024-04-07)
-- [ ] T04: Setup file configurazione (.env, config.py)
+- [x] T04: Setup file configurazione (.env, config.py) (2024-04-07)
 - [ ] T05: Configurare pytest e struttura test
 
 ### 🗄️ Database & Models (T06-T11) - 0/6 completati