End the current work session
Whether a session is currently active (running OR paused)
Whether the active session is currently paused
Pause the active session — no-op when not active or already paused
Resume a paused session — no-op when not active or not paused
Duration of the current session in minutes (excludes paused time)
Start a new work session
Update notes for the current session
The current active session (null if no session is active)