Shorten over-long godoc/inline comments across the client/ui tray and
services code: drop narrative restatement, legacy-Fyne tangents, and text
already evident from signatures and names. Keep only the non-obvious why
(concurrency/lock ordering, platform quirks, ordering constraints, the
profile-switch state table). No code changes.
Removes the legacy fyne-based client/ui implementation and renames the
Wails replacement (client/ui-wails) to take its place at client/ui. Go
imports, frontend bindings, CI workflows, goreleaser configs and the
windows .syso icon path are updated to follow the rename.