Add autosave frequency signal

[jackbdoughty]

literally adds the one signal to standard DAE class for accessing autosave frequency

[Copilot]

Pull Request Overview

Adds support for reading and writing the autosave frequency on the DAE device by introducing a new autosave_freq signal.

• Introduce autosave_freq as a SignalRW[int] bound to the EPICS PV for autosave frequency.
• No other functional changes.

Comments suppressed due to low confidence (1)

src/ibex_bluesky_core/devices/dae/init.py:209

• This new signal isn’t covered by existing unit tests. Consider adding a test to verify that autosave_freq resolves to the correct PV and supports read/write operations as expected.

        self.autosave_freq: SignalRW[int] = isis_epics_signal_rw(int, f"{dae_prefix}AUTOSAVE:FREQ")