fix(wrap): only collapse single-child wrap for split parents

[sim590]

Problem

When a tab group contains a single split child (e.g. t(v(a,b))), hy3:makegroup h with the child group focused does not create a new wrapper. Instead, wrap() takes a shortcut that results in no visible change rather than creating a new wrapper group.

Steps to reproduce:

1. Create a tab group with a vertical split: t(v(a,b))
2. Focus the vertical group with hy3:changefocus raise
3. Run hy3:makegroup h

Expected: t(h(v(a,b)))
Actual: No visible change

Three places assume single-child groups are always redundant, without considering that a split inside a tab is intentional:

• Hy3Node::wrap() reuses the parent when it has one child, regardless of parent type
• shouldCollapseNode() collapses any split-in-split, even inside tabs
• shiftOrGetFocus() traverses through single-child splits even when their parent is a tab

i3 and Sway only apply the single-child shortcut when the parent layout is H or V, not when it is tabbed or stacked.

Changes

• Hy3Node::wrap(): add parentGroup.isSplit() to the single-child shortcut condition
• shouldCollapseNode(): skip split-in-split collapse when the node's parent is a tab group
• makeOppositeGroupOn(): add group.isSplit() to the single-child shortcut condition
• shiftOrGetFocus(): break the traversal loop when the current group's parent is a tab

[sim590]

Hey! Just a heads up... I recently released hypr-layout 0.1.0, a CLI tool for spawning tiled layouts in hy3 (see reddit post). It works well overall, but tab group support relies on this fix to function properly. No rush, just wanted to mention the context in case it helps with prioritization!