v2.0.0

• Remove snapshot serialization and related schema/exception surface, focusing the outbox on payload + aggregate version.
• Rename sequenceNumber → aggregateVersion throughout core code, tests, schema, and docs.
• Standardize tooling/configuration (PHPUnit/PHPStan/PHPCS, reports paths, GitHub workflows, templates).

v1.0.0

• Adds DoctrineOutboxRepository plus supporting schema, SQL-building, and exception types for persisting outbox records inside an existing transaction.
• Introduces payload and snapshot serialization abstractions (including reflection-based defaults) with JSON validation.
• Adds integration/unit tests (including Docker-backed MySQL) plus CI/static-analysis configuration and expanded README documentation.