Release Notes Update: v0.159.2 (#1602)

Co-authored-by: sg-doc-holiday[bot] <219201796+sg-doc-holiday[bot]@users.noreply.github.com>

Author: sg-doc-holiday[bot]

RELEASE_NOTES.md

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+---
+title: Release notes
+---
+
+# Release notes
+
+## v0.159.2 - transaction validation updates
+
+- **Date:** 2026-02-27
+- **Version:** 0.159.2
+
+### Summary
+
+This release includes Conway Plutus transaction validation updates, strict CBOR metadata decoding, and developer documentation refinements.
+
+### Breaking Changes
+
+- Updated Conway Plutus transaction validation to require `ScriptDataHash` only when redeemers or witness datums are present (script references are treated as inert) and to return a typed input-resolution error when a UTxO lookup fails.
+- Updated callers to omit `ScriptDataHash` unless a transaction includes Plutus redeemers or witness datums.
+
+### Bug Fixes
+
+- Fixed metadata decoding for generic CBOR maps to fail fast on any key or value decode error by using `*cbor.Value` map keys.
+
+### Additional Changes
+
+- Updated `AGENTS.md` to clarify delegation behavior, document `TransactionBuilder` and `MockTransaction` usage, and expand validation and review guidelines.