Remove deprecated functionality: FAISS embeddings, file backend, and EFS references

[aarora79]

Summary

Remove deprecated functionality that is no longer needed to reduce codebase complexity and dependencies.

Items to Remove

1. FAISS-based Embeddings Search

• Remove FAISS vector search implementation
• Remove faiss-cpu dependency from pyproject.toml
• This will significantly reduce the virtual environment size (~38 MB for faiss + related libs)

2. File-based Backend

• Remove file-based storage repository implementation
• The project has moved to MongoDB/DocumentDB as the primary storage backend

3. EFS References from Terraform

• Remove all EFS (Elastic File System) references from Terraform infrastructure code
• EFS was used for the file-based backend which is being deprecated

Benefits

• Reduced dependencies: Removing faiss-cpu, torch, sentence-transformers could save ~6GB in the virtual environment
• Simpler codebase: Less code paths to maintain
• Clearer architecture: Single storage backend (MongoDB/DocumentDB) instead of multiple options

Files to Review

• registry/repositories/file/ - File-based repository implementation
• registry/embeddings/ - FAISS and sentence-transformers usage
• pyproject.toml - Dependencies to remove
• terraform/ - EFS module and references

Acceptance Criteria

• All FAISS-related code removed
• File-based backend code removed
• EFS Terraform resources removed
• Dependencies updated in pyproject.toml
• All tests pass after removal
• Documentation updated to reflect changes