Add consumer-facing CHANGELOG.md maintained by release CI.

Backfill version history from git tags and update CHANGELOG automatically on each release alongside Gitea release notes.

Co-authored-by: Cursor <cursoragent@cursor.com>

scripts/ci/backfill-changelog.sh

@@ -0,0 +1,64 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+# shellcheck source=common.sh
+source "${SCRIPT_DIR}/common.sh"
+
+CHANGELOG="CHANGELOG.md"
+
+# Best-effort summary for historical releases without stored PR titles.
+summary_for_range() {
+  local from_ref="$1"
+  local to_ref="$2"
+  local subject
+
+  while IFS= read -r subject; do
+    [[ -z "$subject" ]] && continue
+    if echo "$subject" | grep -qE '^chore: release v'; then
+      continue
+    fi
+    if echo "$subject" | grep -qE "^Merge pull request '"; then
+      local title
+      title=$(extract_pr_title_from_merge_commit "$subject")
+      if [[ -n "$title" ]]; then
+        strip_bump_prefix "$title"
+        return 0
+      fi
+    fi
+    echo "$subject"
+    return 0
+  done < <(git log "${from_ref}..${to_ref}" --pretty=format:'%s' 2>/dev/null || true)
+
+  echo "Release ${to_ref}"
+}
+
+TAGS=()
+while IFS= read -r tag; do
+  TAGS+=("$tag")
+done < <(git tag -l 'v*' --sort=version:refname)
+if [[ ${#TAGS[@]} -eq 0 ]]; then
+  echo "No version tags found." >&2
+  exit 1
+fi
+
+changelog_header > "$CHANGELOG"
+
+for ((i = ${#TAGS[@]} - 1; i >= 0; i--)); do
+  TAG="${TAGS[$i]}"
+  VERSION="${TAG#v}"
+  DATE=$(git log -1 --format=%cs "$TAG" 2>/dev/null || date -u +%Y-%m-%d)
+
+  if [[ $i -eq 0 ]]; then
+    PREV_TAG=""
+  else
+    PREV_TAG="${TAGS[$((i - 1))]}"
+  fi
+
+  SUMMARY=$(summary_for_range "$PREV_TAG" "$TAG")
+  COMMITS=$(commits_between "$PREV_TAG" "$TAG")
+  SECTION=$(changelog_section "$VERSION" "$DATE" "$SUMMARY" "$COMMITS")
+  printf '\n%s\n' "$SECTION" >> "$CHANGELOG"
+done
+
+echo "Generated ${CHANGELOG} from ${#TAGS[@]} tags." >&2