release.sh: drop unused variable; run shellcheck in make test

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

Makefile

@@ -10,6 +10,7 @@ build:
 test:
 	go vet ./...
 	go test ./...
+	@if command -v shellcheck >/dev/null; then shellcheck scripts/*.sh dev/*.sh; else echo "shellcheck not installed, skipping shell script checks"; fi
 
 # Cross-compiled binaries and checksums in dist/.
 dist:

scripts/release.sh

@@ -87,7 +87,6 @@ echo "release: $repo on $base, $tag is free"
 [[ $mode == check ]] && exit 0
 
 # --- release text from the changelog ------------------------------------------
-version=${tag#v}
 python3 - "$tag" "$tmp/release.json" <<'PY' || die "CHANGELOG.md has no section for $tag"
 import json, re, sys
 tag, out = sys.argv[1], sys.argv[2]