feat(vector-db): add Qdrant client

[genaaredes-ui]

PR draft — Add Qdrant REST vector database client

Summary

Adds a Qdrant vector database client to the JavaScript SDK using the HTTP API directly, without adding a Qdrant package dependency.

Supported operations:

• collection creation
• point upsert with embeddings and payloads
• similarity query (/points/query, with legacy /points/search mode)
• paginated scroll and full collection reads
• point retrieval, payload update, and deletion

The client supports API-key authentication, URL-encoded collection/point IDs, injected fetch implementations for tests, and clear HTTP error messages.

Tests

• qdrant.test.ts
• TypeScript compilation passed for the new client.
• Runtime checks passed for the modern /points/query response (result.points) and the legacy /points/search response, plus collection creation, upsert, pagination, and error handling.

Review note

The issue does not state a dollar amount in its GitHub body, so no payment is counted until the maintainer confirms the bounty and merges the PR. No external PR, issue comment, or message has been sent.

The modern response handling follows Qdrant's query-points API, which returns scored points under result.points.

Closes #273

[github-actions]

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