[ISSUE-024] Vector Database Setup

## Phase 5: AI Infrastructure & Meal Planning (Weeks 7-9)

### Description
Set up MongoDB Vector Search or Pinecone
Create recipe embedding generation
Implement similarity search functionality
Index existing recipes

### Dependencies
- #013
- #023

### Can Work in Parallel With
- #023
- #025

Start by reviewing dependencies #013 and #023, then resolve whether the project will use MongoDB Vector Search or Pinecone. The work is done when recipe embeddings are generated, existing recipes are indexed, and similarity search is implemented.

Written by the indexing model from the issue text.