Function dedupeById

apps/sim/lib/copilot/chat/messages-store.ts:12–21

* Keep the first occurrence of each message id. A single `INSERT ... ON * CONFLICT` cannot touch the same conflict target twice, so a repeated id * would otherwise throw.

(messages: PersistedMessage[])

 * would otherwise throw.
 */
function dedupeById(messages: PersistedMessage[]): PersistedMessage[] {
  const seen = new Set<string>()
  const out: PersistedMessage[] = []
  for (const m of messages) {
    if (seen.has(m.id)) continue
    seen.add(m.id)
    out.push(m)
  }
  return out
}

function toRow(
  chatId: string,