feat: Implement assertSchemaIsCorrect and validateSchema functions

[my-lab-23]

Description

Summary of the change: Implements schema validation functions assertSchemaIsCorrect and validateSchema to compare database schema with Exposed table definitions without performing modifications.

Detailed description:

• What: Added two new functions in org.jetbrains.exposed.v1.migration package:
  • assertSchemaIsCorrect(): Throws SchemaValidationException if schema is misaligned
  • validateSchema(): Returns SchemaValidationResult for functional approach
  • Supporting classes: SchemaValidationException and SchemaValidationResult
• Why: Addresses the need for schema validation in CI pipelines, after manual migrations, and in production environments where DDL changes are restricted. Previously, only MigrationUtils.createMissingTablesAndColumns() existed which modifies the database rather than just validating it.
• How: Uses existing MigrationUtils.statementsRequiredForDatabaseMigration() to detect schema differences and provides two API approaches - exception-based for assertions and result-based for functional programming.

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Type of Change

Please mark the relevant options with an "X":

• Bug fix
• New feature
• Documentation update

Affected databases:

• All

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Related Issues

#377

[my-lab-23]

Just brought the branch up to date with main, nothing else changed.