Deduplicate leading verbs in auto-generated changelog entries

[Copilot]

Auto changelog generation was duplicating action words when PR titles already started with a verb (for example, feat: added... rendering as Added added...). This change normalizes entry titles so the changelog prefix and title body do not repeat the same verb.

• What changed

  • Added a prefix-aware verb normalization map in update-changelog.mjs to detect leading forms like add/added/adding, fix/fixed/fixing, revert/reverted, etc.
  • Introduced removeLeadingDuplicateVerb(prefix, title) and applied it during entry construction in buildEntry(...).
  • Kept existing section/prefix resolution behavior (TYPE_TO_SECTION, TYPE_TO_PREFIX) and only adjusted title text generation.

• Behavioral impact

  • feat: added support for X → - Added support for X ...
  • feat: add support for X → - Added support for X ...
  • fix: fixed race condition → - Fixed race condition ...

• Example

  const prefix = TYPE_TO_PREFIX[type] ?? section;
  const dedupedTitle = removeLeadingDuplicateVerb(prefix, cleanedTitle);
  return `- ${prefix} ${dedupedTitle} ([#${prNumber}](${prUrl})) by @${prAuthor}`;