* Enhance MergeResult to track added constraints and indexes.
* Update merge logic to increment counters for added constraints and indexes.
* Modify GetMergeSummary to include constraints and indexes in the output.
* Add comprehensive tests for merging constraints and indexes.
* Implement mergeConstraints to handle table constraints
* Implement mergeIndexes to handle table indexes
* Update mergeTables to include constraints and indexes during merge
- Introduce a new screen for importing and merging database schemas.
- Implement merge logic to combine schemas, tables, columns, and other objects.
- Add options to skip specific object types during the merge process.
- Update main menu to include the new import and merge option.
