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[Idleness76]

v0.3.0 API-breaking consolidation. This release represents the largest breaking change window before v1.0, addressing the highest-friction pain points reported by production users.

Eight planned categories of changes were completed:

• 1: Message.role type safety (String → Role enum)
• 2-alt: Error system redesign (thiserror + optional diagnostics)
• 3: LLM abstraction traits (framework-agnostic)
• 4: Checkpointer extensibility (custom implementations)
• 5: Message conversion implementations (weavegraph ↔ rig)
• 6: README and metadata updates
• 7: Examples audit and consolidation
• 8: Documentation and rustdoc overhaul