Function changeProjectSlug

notfair-cmo/src/server/db/projects.ts:161–234

(
  old_slug: string,
  new_slug: string,
  new_display_name?: string,
)

 * Returns the renamed project, or null when the old slug doesn't exist.
 */
export function changeProjectSlug(
  old_slug: string,
  new_slug: string,
  new_display_name?: string,
): Project | null {
  const db = getDb();
  if (old_slug === new_slug) {
    if (new_display_name) {
      db.prepare("UPDATE projects SET display_name = ? WHERE slug = ?").run(
        new_display_name.trim(),
        old_slug,
      );
    }
    return getProject(old_slug);
  }
  // Bail if the source doesn't exist or the destination already exists.
  if (!db.prepare("SELECT 1 FROM projects WHERE slug = ?").get(old_slug)) {
    return null;
  }
  if (db.prepare("SELECT 1 FROM projects WHERE slug = ?").get(new_slug)) {
    throw new Error(`Project slug '${new_slug}' already exists`);
  }

  const childTables = [
    "tasks",
    "approvals",
    "approval_policies",
    "questions",
    "cost_events",
    "oauth_tokens",
    "mcp_tokens",
    "scheduled_jobs",
    "sessions",
    "agent_actions",
    "sequence_runs",
  ];

  // Disable FK enforcement for the duration of the rename. Our FKs reference
  // `projects(slug)` without ON UPDATE CASCADE, so updating the PK while
  // child rows still point at the old value would violate. `defer_foreign_keys`
  // inside a wrapped transaction doesn't take effect reliably across SQLite
  // releases; toggling `foreign_keys` is universally supported and works the
  // same way every popular SQLite migration tool uses.
  const fkWasOn = db.pragma("foreign_keys = OFF", { simple: true });
  try {
    const tx = db.transaction(() => {
      for (const table of childTables) {
        try {
          db.prepare(`UPDATE ${table} SET project_slug = ? WHERE project_slug = ?`).run(
            new_slug,
            old_slug,
          );
        } catch {
          // table missing on this install; skip.
        }
      }
      if (new_display_name) {
        db.prepare("UPDATE projects SET slug = ?, display_name = ? WHERE slug = ?").run(