[help wanted] Add Pinecone vector store target

[Carlos-Projects]

Task

Add support for scanning Pinecone vector databases as a RAG target.

What to do

• Create src/raguard/targets/pinecone.py
• Implement the VectorStoreTarget interface for Pinecone
• Scan for poisoned vectors, injection points, and policy bypass attempts
• Handle authentication via API key config
• Add tests with mocked Pinecone client

Skills needed

• Python, Pinecone API
• Understanding of RAG security and vector databases

Acceptance criteria

• raguard scan --target pinecone://index-name works
• Auth is handled securely via config/env
• All tests pass and lint is clean

See CONTRIBUTING.md.