feat: support Microsoft SQL Server struct tasks

[gnolong]

Unscoped

• Foreign keys: Extract and recreate column mappings, referential actions, and NOT FOR REPLICATION/disabled/trusted state after data migration.
• Additional schema objects: Support empty schemas, user-defined and table types, views, synonyms, functions, procedures, and DML triggers with dependency ordering.
• Advanced table and column features: Detect and support temporal, ledger, FileTable, external, and graph tables, plus sparse/column-set, masked, encrypted, and other version-specific columns.
• Partitioning and physical options: Preserve partition functions and schemes, filegroups, and index options such as fill factor, padding, and locking flags.
• Extended properties: Migrate arbitrary extended-property names and classes beyond MS_Description on the currently supported owners.
• Catalog consistency and compatibility: Add version/edition-aware catalog projections, a consistent metadata snapshot and retry boundary, and E2E coverage across supported SQL Server versions.
• Ownership and permissions: Migrate schema owners, principals, grants, and other RBAC metadata in a separate final phase.