Remove mandatory Unreleased section requirement from changelog validation

Co-authored-by: jmiller-moko <230051081+jmiller-moko@users.noreply.github.com>

scripts/validate/changelog.sh

@@ -124,18 +124,8 @@ fi
 
 # Core structural checks
 # - Must contain at least one H2 heading with a bracketed version
-# - Must contain an Unreleased section
 # - Must contain a section for the resolved version
 
-unreleased_ok=false
-if grep -Eq '^## \[Unreleased\]' CHANGELOG.md; then
-	unreleased_ok=true
-fi
-
-if [ "${unreleased_ok}" != "true" ]; then
-	fail "CHANGELOG.md missing '## [Unreleased]' section"
-fi
-
 if ! grep -Eq '^## \[[0-9]+\.[0-9]+\.[0-9]+\]' CHANGELOG.md; then
 	fail "CHANGELOG.md has no version sections (expected headings like: ## [x.y.z])"
 fi