feat(profiles): first-class profile switching — phase 0 baseline port (#820)

* feat(profiles): make profile switching actually scope the app (issue #781 follow-up)

* fix(profiles): inherit connection token when switching to same-dashboard profile (issue #781 follow-up)

* fix(chat): reset open session on profile switch + prefill login profile (desktop parity)

* fix(ws): inject profile into profile-scoped RPC params so chat follows the selected profile

* test(chat): de-poison SlashCommandDispatchRpcTest (drop static Dispatchers mock)

mockkStatic(Dispatchers::class) + a stubbed Dispatchers.IO bleeds JVM-wide and
breaks later classes in suite order (CI 2026-08-06: COMMAND_DISPATCH captures
cross-wired → ComparisonFailure on lower stack PRs). ChatViewModel gains an
injected ioDispatcher (38 sites); the slash test constructs the VM with the
test dispatcher so the IO stub is unnecessary.

---------

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

app/src/test/java/com/m57/hermescontrol/ui/connect/ConnectViewModelTest.kt

@@ -392,7 +392,7 @@ class ConnectViewModelTest {
     }
 
     @Test
-    fun testLoadSavedValues_withStaleSelectedId_fallsBackToDefaults() {
+    fun testLoadSavedValues_withStaleSelectedId_prefillsSelectedId() {
         val profile =
             ConnectionProfile(
                 id = "prof-1",
@@ -407,7 +407,10 @@ class ConnectViewModelTest {
         val state = viewModel.uiState.value
 
         assertNull(state.selectedProfile)
-        assertEquals("", state.profileName)
+        // Profile name prefills the selected id so a re-login after switching
+        // to a profile created in-app (no saved connection yet) stays on that
+        // profile instead of silently landing back on default.
+        assertEquals("nonexistent-id", state.profileName)
         assertEquals("https://127.0.0.1:9119/", state.baseUrl)
     }