Add Qdrant vector database client

[milesfeldstein]

Summary

• add a Qdrant vector database wrapper for the JavaScript SDK using direct Qdrant REST API calls through the existing Axios dependency
• export the Qdrant class and related point/vector/payload types from the vector-db package entrypoint
• cover client creation, point upsert, vector query, and point deletion with Vitest tests

/claim #273
Fixes #273

Validation

• npm run build
• npx vitest run src/vector-db/src/tests/qdrant/qdrant.test.ts

Notes

• The full repo test suite still has unrelated existing failures: multiple suites use Jest globals while the package script runs Vitest, and scraper tests require network/Playwright/browser credentials.

[github-actions]

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