Method getOrCreateThread

server/src/addie/thread-service.ts:298–322

* Create or get a thread by channel + external_id * Uses UPSERT to handle concurrent requests safely

(input: CreateThreadInput)

   * Uses UPSERT to handle concurrent requests safely
   */
  async getOrCreateThread(input: CreateThreadInput): Promise<Thread> {
    const result = await query<Thread>(
      `INSERT INTO addie_threads (
        channel, external_id, user_type, user_id, user_display_name,
        context, title, impersonator_user_id, impersonation_reason
      ) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)
      ON CONFLICT (channel, external_id) DO UPDATE SET
        user_display_name = COALESCE(EXCLUDED.user_display_name, addie_threads.user_display_name),
        context = COALESCE(EXCLUDED.context, addie_threads.context),
        updated_at = NOW()
      RETURNING *`,
      [
        input.channel,
        input.external_id,
        input.user_type || 'anonymous',
        input.user_id || null,
        input.user_display_name || null,
        JSON.stringify(input.context || {}),
        input.title || null,
        input.impersonator_user_id || null,
        input.impersonation_reason || null,
      ]
    );
    return result.rows[0];
  }

  /**
   * Get a thread by ID