fix: Restore schema-only and time filter steps in interactive wizard (#9)

The interactive wizard was rewritten in commit 6964e4f to add back
navigation support, but the schema-only and time filter selection
steps were accidentally removed.

This commit restores the full 5-step wizard:
1. Select databases
2. Select tables to exclude
3. Select schema-only tables (no data replication)
4. Configure time-based filters
5. Review and confirm

Also adds:
- Table caching to avoid repeated database queries when navigating back
- Timestamp column discovery for time filter configuration
- Proper TableRules construction from wizard selections

Closes #194

Author: taariq