list-windows sorting: Unify multiple PR approaches for DFS and custom ordering

[kim-raaschou-nielsen]

Summary:
Multiple PRs show strong community demand for enhanced list-windows sorting, particularly DFS (depth-first search) ordering. Three separate efforts are addressing overlapping functionality, and unifying these approaches would benefit the project.

Background:
The current list-windows command sorts alphabetically by app name and title. Users increasingly need DFS ordering to match window tree structure (for status bars, scripts, and focus --dfs-index consistency) and custom sorting by recency or other criteria.
Related Issues/PRs

1. Feature Request: Implement list-windows --sort-by #491 - Original feature request for DFS-ordered window listing
2. Add --sort tree-order flag to list-windows command #1839 - First attempt with --sort tree-order flag (closed)
3. add list-windows --sort-by #1918 - Implements --sort-by dfs-index + DFS structure change detection
4. list-windows: add --sort option #1932 - Implements --sort with options: recent, app-name, window-title

The Problem:
With one closed PR (#1839) and two open PRs (#1918, #1932) addressing similar needs, this is clearly a critical feature. However, the overlapping implementations use different flag names (--sort-by vs --sort) and have different scopes: #1918 adds DFS ordering plus structure change detection for exec-on-workspace-change callbacks, while #1932 provides flexible sorting with multiple criteria. Both maintain backward compatibility, but having competing approaches risks fragmented effort and inconsistent UX.

Path Forward:
Rather than choosing one PR over another, the community would benefit from discussing unification:

1. Should all sorting options live under one flag (e.g., --sort supporting: dfs-index, recent, app-name, window-title)?
2. Is DFS change detection from add list-windows --sort-by #1918 desired as part of this or separate?
3. Should we prioritize DFS ordering first, then add other options later?

Request:
Guidance on the preferred approach before proceeding further would be appreciated. This would help move forward efficiently with an implementation strategy that serves the community's needs.