List of `InstrumentSessions` must be provided with `AppProviders`

Currently the list of potential Instrument Sessions is hard coded and passed to the `InstrumentSessionProvider`, this doesn't allow for dynamic fetching of Instrument Sessions based on who is logged in, or which sessions are currently open.

The `InstrumentSessionProvider` should store and read this list from `localStorage`, like it does to determine the current active session.

In the long-term, this list should be populated each time a user logs in (and removed when they log out).

For this to be useful for I15-1, there should be a way to fire off the query which fetches the available instrument sessions in the short term, likely on the dashboard.

Start by tracing how AppProviders supplies the hard-coded list to InstrumentSessionProvider, then inspect the provider's existing localStorage handling for the active session. Identify the dashboard entry point for fetching available instrument sessions. Done means the provider reads the session list from localStorage and the short-term dashboard query path is defined without relying on a hard-coded list.

Written by the indexing model from the issue text.