Routines: add setting to set Calendar as the default tab

Question

## Feature request

**Current behavior:**
The Routines view always opens on the "All" tab. The "Calendar" tab must be clicked manually every time.

**Desired behavior:**
Add a user preference (e.g. in Settings or as a persistent tab selection) to set "Calendar" as the default tab when opening the Routines view.

**Why this matters:**
The Calendar view is often more useful for users who want to see upcoming scheduled runs in a timeline view rather than a flat list. Having to switch tabs on every