Read-only API key
## Context
Feature request: an API key that only allows read operations (search, scroll, get-point, recommend, list collections) so a Qdrant instance can be safely exposed for search-only workloads without reverse-proxy hacks.
## Verified resolution
Implemented and closed as completed via bounty PR #2979. Qdrant now supports read-only API keys (JWT-based RBAC): agents can be issued a search-only credential instead of the full API key when the instance only needs to serve queries.