* fix(mobile): persist per-device tab selection so worktree return restores the last open tab
A phone's tab selection lived only in the host's in-memory
ClientSessionTabSelectionStore. Any host restart wiped it, and the
per-device projection then fell back to deterministic topology, so
returning to a worktree on mobile always landed on the first tab
instead of the tab last opened on the phone.
Persist the per-device selections in the Store (keyed deviceId ->
worktreeId), hydrate them when the runtime constructs, and guard
projection so an early empty snapshot after restart cannot wipe a
hydrated selection before tabs arrive. Selections are pruned with the
worktree/repo and on device revoke, and malformed persisted payloads
degrade to empty instead of throwing.
* fix(mobile): harden persisted tab selection cleanup
* fix(mobile): preserve tab selection across worktree rename