The UI never needs to block on Up — status updates flow via the
SubscribeStatus stream. Hardcode Async:true in Connection.Up and remove
the Async field from UpParams so frontend callers are unaffected.
The daemon's Up RPC previously always blocked in waitForUp (up to 50s)
until the engine connected. The UI does not need this — status updates
already flow through the SubscribeStatus stream.
Add bool async = 4 to UpRequest. When true the daemon starts
connectWithRetryRuns and returns immediately; the CLI path (async=false,
the default) is unchanged.
ProfileSwitcher.SwitchActive now sets Async:true so all three RPCs
(Status, Switch, Down, Up) return quickly. The background goroutine and
its associated race condition are removed entirely.
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.
