Release 0.3.0

[AltiAntonov]

Summary

Add structured safe-decoding issue reporting through SafeDecodingReport and SafeDecodingDiagnostics.capture without changing the existing wrapper behavior.

Added

• SafeDecodingReport for structured issue inspection
• SafeDecodingDiagnostics.capture for returning a decoded value plus a scoped report
• reporting coverage for clean payloads, fallback-backed issues, mixed-wrapper ordering, nested coding paths, throw behavior, and handler composition

Changed

• README now documents report capture and the 0.3.0 release path
• changelog now describes 0.3.0 as an additive, non-breaking reporting release
• wrapper behavior remains unchanged; reporting is now observable as structured data

Breaking Changes

• None.