feat: Add MySQL to PostgreSQL migration tool with JSONB transformation

Implement comprehensive migration solution with:
- Full and incremental migration modes
- JSONB schema transformation for RAWDATACOR and ELABDATADISP tables
- Native PostgreSQL partitioning (2014-2031)
- Optimized GIN indexes for JSONB queries
- Rich logging with progress tracking
- Complete benchmark system for MySQL vs PostgreSQL comparison
- CLI interface with multiple commands (setup, migrate, benchmark)
- Configuration management via .env file
- Error handling and retry logic
- Batch processing for performance (configurable batch size)

Database transformations:
- RAWDATACOR: 16 Val columns + units → single JSONB measurements
- ELABDATADISP: 25+ measurement fields → structured JSONB with categories

🤖 Generated with Claude Code

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

.env.example

@@ -0,0 +1,22 @@
+# MySQL Source Database
+MYSQL_HOST=localhost
+MYSQL_PORT=3306
+MYSQL_USER=root
+MYSQL_PASSWORD=your_mysql_password
+MYSQL_DATABASE=your_database_name
+
+# PostgreSQL Target Database (container Incus)
+POSTGRES_HOST=localhost
+POSTGRES_PORT=5432
+POSTGRES_USER=postgres
+POSTGRES_PASSWORD=your_postgres_password
+POSTGRES_DATABASE=migrated_db
+
+# Migration Settings
+BATCH_SIZE=10000
+LOG_LEVEL=INFO
+DRY_RUN=false
+
+# Performance Testing
+BENCHMARK_OUTPUT_DIR=benchmark_results
+BENCHMARK_ITERATIONS=5