fix: Add last_completed_partition column to migration_state table schema

The migration_state table was missing the last_completed_partition column
that was referenced in the migration update queries. This column tracks
which partition was last completed to enable accurate resume capability.

To apply this change to existing databases:
  ALTER TABLE migration_state ADD COLUMN last_completed_partition VARCHAR(255);

For new databases, the table will be created with the column automatically.

pyproject.toml

@@ -12,4 +12,5 @@ dependencies = [
     "rich>=13.0.0",
     "pydantic>=2.5.0",
     "pydantic-settings>=2.1.0",
+    "cryptography>=46.0.3",
 ]