Add ability to save and revisit multiple tailored résumé versions

[saviobatista]

Business Value
Users may want to apply to multiple jobs and compare résumé variations. Saving versions allows reuse and refinement over time.

Description
Implement client-side or backend logic to store tailored résumé sessions and allow users to revisit or regenerate from history.

Technical Details

• Store résumé sessions as local JSON (MVP) or in Supabase (later)
• Each version should include:
  • Job description
  • Structured résumé
  • AI output
  • Selected template
• Add /app/history route to list and view versions

Acceptance Criteria

• User can name and save each résumé version
• Versions can be listed and reopened
• Reopening restores data into builder/export flow