chore: import upstream snapshot with attribution

scripts/generate_release_notes.sh

@@ -0,0 +1,159 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Generate a human-readable release notes body for a jcode release (issue #435).
+#
+# Usage:
+#   scripts/generate_release_notes.sh <tag> [previous-tag]
+#
+# Behavior:
+#   1. If changelog/v<version>.json exists (schema in changelog/README.md),
+#      render it into Highlights / Improvements / Fixes markdown sections.
+#   2. Otherwise, group commit subjects between the previous tag and <tag>
+#      by conventional-commit prefix (feat/fix/perf/docs/other).
+#   Always appends the GitHub compare link at the bottom.
+
+TAG="${1:?Usage: scripts/generate_release_notes.sh <tag> [previous-tag]}"
+PREV_TAG="${2:-}"
+
+cd "$(git rev-parse --show-toplevel)"
+
+VERSION_NUM="${TAG#v}"
+CHANGELOG_FILE="changelog/v${VERSION_NUM}.json"
+
+# Determine the owner/repo slug for the compare link.
+repo_slug() {
+    if [[ -n "${GITHUB_REPOSITORY:-}" ]]; then
+        echo "$GITHUB_REPOSITORY"
+        return
+    fi
+    local url
+    url="$(git remote get-url origin 2>/dev/null || true)"
+    if [[ "$url" =~ github\.com[:/]+([^/]+/[^/ ]+) ]]; then
+        echo "${BASH_REMATCH[1]%.git}"
+        return
+    fi
+    echo "1jehuang/jcode"
+}
+
+REPO="$(repo_slug)"
+
+# Determine the previous tag if not supplied: nearest ancestor tag first,
+# falling back to the next entry in version-sorted tag order.
+if [[ -z "$PREV_TAG" ]]; then
+    if git rev-parse -q --verify "refs/tags/$TAG" >/dev/null; then
+        PREV_TAG="$(git describe --tags --abbrev=0 "$TAG^" 2>/dev/null || true)"
+    fi
+    if [[ -z "$PREV_TAG" ]]; then
+        PREV_TAG="$(git tag -l 'v*' --sort=-v:refname \
+            | grep -A1 -Fx "$TAG" | tail -n +2 | head -1 || true)"
+    fi
+fi
+
+# Render changelog/v<version>.json into markdown sections.
+render_changelog_json() {
+    python3 - "$CHANGELOG_FILE" << 'PY'
+import json
+import sys
+
+with open(sys.argv[1], encoding="utf-8") as f:
+    entry = json.load(f)
+
+out = []
+title = entry.get("title")
+if title:
+    out.append(f"**{title}**")
+    out.append("")
+
+for key, heading in (
+    ("highlights", "Highlights"),
+    ("improvements", "Improvements"),
+    ("fixes", "Fixes"),
+):
+    items = entry.get(key) or []
+    if not items:
+        continue
+    out.append(f"### {heading}")
+    out.append("")
+    out.extend(f"- {item}" for item in items)
+    out.append("")
+
+print("\n".join(out).rstrip())
+PY
+}
+
+# Fallback: group commit subjects since the previous tag by
+# conventional-commit prefix.
+render_commit_fallback() {
+    local range
+    local end_ref="$TAG"
+    # Support pre-tag dry runs where the tag does not exist yet.
+    if ! git rev-parse -q --verify "$TAG^{commit}" >/dev/null; then
+        end_ref="HEAD"
+    fi
+    if [[ -n "$PREV_TAG" ]]; then
+        range="$PREV_TAG..$end_ref"
+    else
+        range="$end_ref"
+    fi
+
+    python3 - "$range" << 'PY'
+import re
+import subprocess
+import sys
+
+subjects = subprocess.run(
+    ["git", "log", "--no-merges", "--pretty=format:%s", sys.argv[1]],
+    check=True,
+    capture_output=True,
+    text=True,
+).stdout.splitlines()
+
+groups = {"feat": [], "fix": [], "perf": [], "docs": [], "other": []}
+pattern = re.compile(r"^(feat|fix|perf|docs)(\([^)]*\))?!?:\s*(.+)$", re.IGNORECASE)
+for subject in subjects:
+    subject = subject.strip()
+    if not subject:
+        continue
+    match = pattern.match(subject)
+    if match:
+        groups[match.group(1).lower()].append(match.group(3).strip())
+    else:
+        groups["other"].append(subject)
+
+out = []
+for key, heading in (
+    ("feat", "Features"),
+    ("fix", "Fixes"),
+    ("perf", "Performance"),
+    ("docs", "Documentation"),
+    ("other", "Other changes"),
+):
+    items = groups[key]
+    if not items:
+        continue
+    out.append(f"### {heading}")
+    out.append("")
+    out.extend(f"- {item}" for item in items)
+    out.append("")
+
+print("\n".join(out).rstrip())
+PY
+}
+
+if [[ -f "$CHANGELOG_FILE" ]]; then
+    BODY="$(render_changelog_json)"
+else
+    BODY="$(render_commit_fallback)"
+fi
+
+if [[ -n "$BODY" ]]; then
+    printf '%s\n\n' "$BODY"
+fi
+
+if [[ -n "$PREV_TAG" ]]; then
+    printf '**Full changelog**: https://github.com/%s/compare/%s...%s\n' \
+        "$REPO" "$PREV_TAG" "$TAG"
+else
+    printf '**Full changelog**: https://github.com/%s/commits/%s\n' "$REPO" "$TAG"
+fi