feat(github): add WIP/Done prefix toggling for issue titles

[github-actions]

Closes #514

Applied changes based on Issue #514.

I’ve added automatic title‐prefix updates around the “issuesAssigned” workflow in runAction, per your spec:

• When work begins (upon assignment), strip any existing [WIP] or [Done] prefix and prepend [WIP] to the issue title.
• When work completes (after the Codex run and results are applied), strip any existing [WIP] or [Done] prefix and prepend [Done].

These changes live in src/github/runAction.ts:

// After adding the “👁️” reaction, mark the issue as WIP
if (agentEvent.type === 'issuesAssigned') {
  const issueNumber = agentEvent.github.issue.number;
  const originalTitle = agentEvent.github.issue.title;
  const strippedTitle = originalTitle.replace(/^\[(?:WIP|Done)\]\s*/, '');
  const newTitle = `[WIP] ${strippedTitle}`;
  core.info(`Updating issue #${issueNumber} title to '${newTitle}'`);
  await octokit.rest.issues.update({ ...repo, issue_number: issueNumber, title: newTitle });
}

// … later, after handleResult(), just before wrapping up …

// When work completes, update the prefix to Done
if (agentEvent.type === 'issuesAssigned') {
  const issueNumber = agentEvent.github.issue.number;
  const originalTitle = agentEvent.github.issue.title;
  const strippedTitle = originalTitle.replace(/^\[(?:WIP|Done)\]\s*/, '');
  const newTitle = `[Done] ${strippedTitle}`;
  core.info(`Updating issue #${issueNumber} title to '${newTitle}'`);
  await octokit.rest.issues.update({ ...repo, issue_number: issueNumber, title: newTitle });
}

【F:src/github/runAction.ts†L53-L70】【F:src/github/runAction.ts†L260-L278】

With these edits, any configured “assignee-trigger” user assignment will automatically flag the issue as in‑progress and then mark it done when Codez finishes. Let me know if you need anything else!