feat(setup): T05 configure pytest with coverage

- Create pytest.ini with:
  - Test discovery configuration (testpaths, python_files)
  - Asyncio mode settings
  - Coverage configuration (>=90% requirement)
  - Custom markers (unit, integration, e2e, slow)
- Update conftest.py with:
  - pytest_asyncio plugin
  - Shared fixtures (project_root, src_path, temp_dir, mock_env_vars)
  - Path configuration for imports
- Add test_pytest_config.py with 12 unit tests
- All tests passing (12/12)

Refs: T05

Completes setup phase T01-T05

export/progress.md

@@ -8,13 +8,13 @@
 
 | Metrica | Valore |
 |---------|--------|
-| **Stato** | 🟡 In Progress |
-| **Progresso** | 5% |
+| **Stato** | 🟢 Setup Completato |
+| **Progresso** | 7% |
 | **Data Inizio** | 2024-04-07 |
 | **Data Target** | TBD |
 | **Task Totali** | 74 |
-| **Task Completati** | 4 |
-| **Task In Progress** | 1 |
+| **Task Completati** | 5 |
+| **Task In Progress** | 0 |
 
 ---
 
@@ -37,12 +37,12 @@
 
 ## 📋 Task Pianificate
 
-### 🔧 Setup Progetto (T01-T05) - 4/5 completati
+### 🔧 Setup Progetto (T01-T05) - 5/5 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)
 - [x] T04: Setup file configurazione (.env, config.py) (2024-04-07)
-- [ ] T05: Configurare pytest e struttura test
+- [x] T05: Configurare pytest e struttura test (2024-04-07)
 
 ### 🗄️ Database & Models (T06-T11) - 0/6 completati
 - [ ] T06: Creare database.py (connection & session)