Module error_taxonomy 

Shared error classification enums for tool invocation failures.

Only the pure data types (ToolErrorCategory and ErrorDomain) live here. The classify_* helper functions and executor-specific types remain in zeph-tools, which may depend on std::io::Error and HTTP status codes.

Enums

ErrorDomain

High-level error domain for recovery strategy dispatch.

ToolErrorCategory

Fine-grained 12-category classification of tool invocation errors.

ToolInvocationPhase

Invocation phase in which a tool failure occurred, per arXiv:2601.16280.