Add Qdrant vector database client

[HunterCML]

Summary

• add a fetch-backed Qdrant vector database client for the JavaScript SDK
• export Qdrant from the vector-db package
• cover collection creation, point upsert, vector search, point deletion, and client setup with unit tests

Notes

• implements Qdrant API calls directly without the Qdrant package
• uses QDRANT_URL and optional QDRANT_API_KEY, defaulting to http://localhost:6333

Validation

• npx tsc --noEmit --target ES2022 --module NodeNext --moduleResolution NodeNext --esModuleInterop --strict --skipLibCheck --types jest,node .\src\vector-db\src\lib\qdrant\qdrant.ts
• runtime smoke test against a fake client for create collection, insert, search, and delete paths

Repo-level check notes

• npm run build currently fails on Windows before TypeScript because the script uses rm -rf dist
• full npx tsc -b is blocked by existing unrelated errors in hono, node-html-parser, and youtubeLoader.ts
• targeted npx jest src/vector-db/src/tests/qdrant/qdrant.test.ts --runInBand is blocked by the current local install missing Jest transitive packages (jest-haste-map, exit)

/claim #273

[github-actions]

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[HunterCML]

I have read the Arakoo CLA Document and I hereby sign the CLA