The tray now switches to a dedicated lock icon when the daemon reports
NeedsLogin, SessionExpired or LoginFailed — the latter mirrors the CLI,
which groups these three statuses together as "needs authentication"
and prints the same "Run netbird up" prompt. The macOS template variant
reuses the existing error-macos PNG because the project's macOS tray
PNGs use a 2-color (black + transparent) convention that rsvg-convert
of the badge-style SVG sources can't reproduce. The earlier badge-style
SVG sketches in assets/svg/ are removed (they were marked as reference
only and never matched the shipping PNG design).
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.
