fix(pack): valid manifest YAML, stable-release picker, tolerant asset re-upload

- manifest: single-quote the coa-template note - nested double quotes
  made the scalar invalid YAML (awk include-parser unaffected; it only
  reads repo:/include: lines)
- build_pack: releases?limit=1 could hand back a prerelease/draft;
  fetch limit=10 and jq-select the first stable release
- release.yml: re-running for an existing tag 409'd on duplicate asset
  names and set -euo pipefail killed the job; skip already-attached
  assets / warn on failed uploads and only fail when the release ends
  up with zero assets

tools/build_pack.sh

@@ -78,13 +78,14 @@ manifest_includes() {
   ' "$MANIFEST"
 }
 
-# Latest release JSON for a repo, or empty string if none.
+# Latest stable release JSON for a repo, or empty string if none.
 latest_release_json() {
   local repo="$1" json
-  json="$(curl -fsS "$API/repos/$ORG/$repo/releases?limit=1" 2>/dev/null || echo '[]')"
-  # `releases?limit=1` returns an array. Strip the wrapper.
+  json="$(curl -fsS "$API/repos/$ORG/$repo/releases?limit=10" 2>/dev/null || echo '[]')"
+  # `releases?limit=N` returns a newest-first array that can contain
+  # prereleases/drafts - pick the first stable release.
   if [ "$(printf '%s' "$json" | jq -r 'type')" = "array" ]; then
-    printf '%s' "$json" | jq -c '.[0] // empty'
+    printf '%s' "$json" | jq -c '[.[] | select(.prerelease == false and .draft == false)][0] // empty'
   else
     printf ''
   fi