#3516 refactor: Formalize our exception hierarchy Pull request opened by edgarrmondragon SSIA Summary by Sourcery Introduce a formal, centralized exception hierarchy for the Singer SDK and document its design and usage. New Features: • Add a common SingerSDKError root base class and structured intermediate exception types for configuration, discovery, mapping, sync, and lifecycle control-flow. • Expose a curated all export list for all public SDK exceptions. • Add detailed implementation and design documentation for the exception hierarchy, including guidance on choosing exception types. Enhancements: • Refactor existing exceptions to inherit from the new hierarchy rather than directly from Exception, preserving existing names for backward compatibility. • Introduce IgnorableSyncError, DataError, SyncLifecycleSignal, and other semantic groupings to encode recovery behavior in exception types. • Clarify lifecycle-related abort and pause exceptions by grouping them under a dedicated SyncLifecycleSignal base class. • Add project contributor guidance in CLAUDE.md on where and how to define new exceptions and how to extend the hierarchy. Documentation: • Add an implementation reference section for errors, documenting the full exception hierarchy and design rationale, and link it into the implementation index. meltano/sdk