- Renamed existing messages table to `messages_deprecated`
- Created new `messages` table with updated schema and additional indexes
- Updated Diesel schema to reflect new table structure and relationships
- Added new foreign key constraints for threads and users
- Prepared for migration of existing message data
- Created `messages_to_files` junction table to link messages with dashboard and metric files
- Added foreign key constraints and indexes for efficient file-message relationships
- Updated Diesel schema to include new `messages_to_files`, `dashboard_files`, and `metric_files` tables
- Removed unnecessary timestamp triggers from migration files