CSO-26: Fix duplicate Airtable table handling when creating resume books

[shanoysinc]

Description ✏️

Closes #xxx

This PR fixes an issue where creating a resume book could fail if the corresponding Airtable table already existed.

Changes

• Check whether the Airtable table already exists before attempting to create it.
• Reuse the existing Airtable table ID when creating the resume book if the table already exists.
• Prevent duplicate resume books by returning an error when a resume book with the same name already exists.
• Improve the resume book creation flow to gracefully handle existing Airtable resources.

Type of Change 🐞

• Feature - A non-breaking change which adds functionality.
• Fix - A non-breaking change which fixes an issue.
• Refactor - A change that neither fixes a bug nor adds a feature.
• Documentation - A change only to in-code or markdown documentation.
• Tests - A change that adds missing unit/integration tests.
• Chore - A change that is likely none of the above.

Checklist ✅

• I have done a self-review of my code.
• I have manually tested my code (if applicable).
• I have added/updated any relevant documentation (if applicable).