Feature Request: Option to show only current workspace windows in App Switcher (Alt+Tab)

## Description Currently, the Alt+Tab (App Switcher) in COSMIC shows windows from **all workspaces**, which makes it very easy to lose track of what you're working on when using multiple workspaces. ## Request Add an option in **Settings → Desktop → Window Management → App Switcher** to toggle: - **"Show windows from all workspaces"** (current behavior) - **"Show only windows from current workspace"** (requested behavior) ## Use Case Users who organize their workflow by separating apps into different workspaces (e.g., Workspace 1 = Browser, Workspace 2 = IDE/Terminal, Workspace 3 = Communication) would benefit greatly from being able to Alt+Tab only within the current workspace without seeing windows from other workspaces. ## Reference This is a standard feature in GNOME (via `gsettings set org.gnome.shell.app-switcher current-workspace-only true`) and other DEs, and many users migrating from Pop!_OS 22.04 (GNOME-based) miss this functionality. ## Environment - OS: Pop!_OS 24.04 - COSMIC version: latest Thank you for the amazing work on COSMIC! 🚀