chore: eliminate all Kotlin compiler warnings in main source (#877)

* chore: eliminate all Kotlin compiler warnings in main source

* test(chat): fix cross-class coroutine leaks poisoning the unit suite

- ChatUpdateCommandTest: inject FakeSlashUsageStore — the real DataStore
  store inits on real IO threads with a relaxed-mock app (cacheDir NPE)
  and leaks an uncaught exception into the next runTest class.
- ChatUpdateCommandTest + SlashCommandDispatchRpcTest: mock
  ProfileSwitchCoordinator.switched (ChatViewModelTest pattern) — VMs
  otherwise park collectors on the singleton flow that crash later
  classes (ProfileSwitchCoordinatorTest) on stale-Main resumption.

Full suite: 944 tests, 0 failures (was 2 flaky per run).

---------

Co-authored-by: M57 <hy4ri@users.noreply.github.com>

app/src/main/java/com/m57/hermescontrol/ui/toolsets/ToolsetDetailViewModel.kt

@@ -288,7 +288,7 @@ class ToolsetDetailViewModel : ViewModel(), ToastHost {
                                     state.copy(
                                         postSetup =
                                             state.postSetup?.copy(
-                                                lines = data.lines ?: state.postSetup?.lines ?: emptyList(),
+                                                lines = data.lines ?: state.postSetup.lines,
                                                 running = data.running == true,
                                                 exitCode = data.exit_code,
                                             ),