Add comprehensive validation system and migrate to .env configuration

This commit includes:

1. Database Configuration Migration:
   - Migrated from DB.txt (Java JDBC) to .env (python-dotenv)
   - Added .env.example template with clear variable names
   - Updated database.py to use environment variables
   - Added python-dotenv>=1.0.0 to dependencies
   - Updated .gitignore to exclude sensitive files

2. Validation System (1,294 lines):
   - comparator.py: Statistical comparison with RMSE, correlation, tolerances
   - db_extractor.py: Database queries for all sensor types
   - validator.py: High-level validation orchestration
   - cli.py: Command-line interface for validation
   - README.md: Comprehensive validation documentation

3. Validation Features:
   - Compare Python vs MATLAB outputs from database
   - Support for all sensor types (RSN, Tilt, ATD)
   - Statistical metrics: max abs/rel diff, RMSE, correlation
   - Configurable tolerances (abs, rel, max)
   - Detailed validation reports
   - CLI and programmatic APIs

4. Examples and Documentation:
   - validate_example.sh: Bash script example
   - validate_example.py: Python programmatic example
   - Updated main README with validation section
   - Added validation workflow and troubleshooting guide

Benefits:
- ✅ No Java driver needed (native Python connectors)
- ✅ Secure .env configuration (excluded from git)
- ✅ Comprehensive validation against MATLAB
- ✅ Statistical confidence in migration accuracy
- ✅ Automated validation reports

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

sync_server_file.sh

@@ -40,14 +40,19 @@ find "${LOCAL_DST}" -type f -name "*.m" -print0 | xargs -0 git add
 
 # 5. Esegui il commit con il messaggio datato
 echo "Eseguo il commit con messaggio: \"${COMMIT_MSG}\""
+CHANGED_FILES_NUM=$(git diff --staged --name-only | wc -l)
+CHANGED_FILES=$(git diff --staged --name-only)
+
 git commit -m "${COMMIT_MSG}"
 
 # 6. Verifica se il commit ha prodotto modifiche
 if [ $? -eq 0 ]; then
     echo "Commit completato con successo."
+    echo "Numero di file modificati/aggiunti: ${CHANGED_FILES_NUM}"
+    # comando a claude per vedere i file cambiati e verificare le modifiche da riportare nella traduzione python
 else
     # Questo succede se non ci sono state modifiche (rsync non ha trovato nulla da aggiornare)
     echo "Nessuna modifica rilevata; commit saltato."
 fi
 
-echo "Processo completato."
+echo "Processo sync completato."