Add altor-vec to Full Text Search section

[anshulbasia27]

altor-vec

altor-vec is an in-browser HNSW vector search engine compiled to 54KB of WebAssembly.

Why it belongs in Full Text Search alongside lunr / flexsearch / Elasticlunr:

• Runs entirely in the browser with no server required
• Sub-millisecond search (0.6ms p95 for 10K vectors in Chrome)
• Semantic/vector search rather than keyword matching: 'cancel subscription' finds 'end your plan'
• npm install altor-vec, MIT licensed
• Docs: https://altorlab.dev

It fills a gap in this section: lunr and flexsearch are keyword-based; altor-vec is the browser-native option for semantic vector search.