Add optional tab groups

[SamarthaB10]

Why

Search has a flat tab list. People with many open tabs need a way to keep related tabs together and hide a group without closing its pages. The roadmap lists tab groups as later work.

Proposed behavior

• Add an optional Tab Groups setting, off by default.
• Create a named, colored group from a tab's context menu. Use "Group N" until the user sets a name.
• Show group labels in both tab layouts. Click a label to expand or collapse its tabs.
• Drag tabs into and out of groups, and move a group as a unit.
• Save normal tabs and group state across launches. Keep private tabs temporary and pinned tabs outside groups.
• Keep existing keyboard tab navigation and make selected tabs visible by opening their group.

The change should use Search's current SwiftUI controls and add no dependency.

[driceroland]

Good news: tab groups are now planned, as an option that's off by default. #242 by @isaiasroliveira is the version being built on, with named groups in the sidebar and in the row across the top. It still has to be fitted to everything else (Spaces, pins, private tabs), so there's no date yet, and this stays open until it lands.

[driceroland]

Fixed in Search 1.0.4, out now: https://github.com/driceroland/Search/releases/tag/v1.0.4. Search updates itself, or get it at https://officecommun.com/search. Thank you for the report! If it still happens on 1.0.4, reopen this and tell us.