Historian Query API

With #4911 established, particularly the "Historian" databse, a natural follow-on to this would be a low-code query layer to empower users to gain insights and query their historical data generated on their Broker.

- Simple: SQL query interface to the Historian
- Ambitious: Natural Language Query Layer
- We want to make this as low-code as possible, as natural language doesn't get much lower-code.
- We could make this an interface in FlowFuse, but also offer built-in nodes for the Node-RED experience should users want to build their own too.

No implementation files or tests are named. Start by reading issue #4911 and the Historian database work it establishes, then clarify whether the scope is a SQL query interface, a natural-language layer, or both. Done would require an agreed query experience for historical Broker data, with its FlowFuse and Node-RED integration defined.

Written by the indexing model from the issue text.